HRVs: What Are They and What Do They Do?
In today’s world, where energy efficiency and indoor air quality are becoming increasingly important, Heat Recovery Ventilators (HRVs) have emerged as a crucial solution for homeowners and building managers alike. But what exactly is an HRV, how does it work, and why is it so vital for modern living? Let’s dive into the details.
What is an HRV?
A Heat Recovery Ventilator (HRV) is a mechanical ventilation system designed to provide fresh air while conserving energy. It works by transferring heat from the outgoing stale air to the incoming fresh air, ensuring that your home remains comfortable without excessive energy loss. HRVs are especially beneficial in well-insulated homes where natural ventilation may not be sufficient.
How Does an HRV Work?
An HRV operates through a two-stream system: one for incoming fresh air and another for outgoing stale air. Here’s a step-by-step breakdown of its standard operation:
Stale Air Exhaust: The HRV draws stale, humid air from inside the home (typically from areas like kitchens and bathrooms) and expels it outside.
Heat Exchange: As the stale air is expelled, it passes through a heat exchanger—a key component of the HRV. Here, the heat from the outgoing air is transferred to the incoming fresh air without the two air streams mixing.
Fresh Air Intake: Simultaneously, the HRV pulls fresh outdoor air into the home. The incoming air is warmed by the heat exchanged from the outgoing air, making it more comfortable before it enters living spaces.
Distribution: The pre-conditioned fresh air is then distributed throughout the home, ensuring a continuous supply of clean air.
Humidity Control: HRVs also help manage humidity levels by removing excess moisture from the indoor environment, which can be particularly beneficial in climates with high humidity.
Why Are HRVs Used?
1. Energy Efficiency
One of the primary reasons HRVs are widely adopted is their ability to improve energy efficiency. By recovering heat from the outgoing air, they significantly reduce the energy required to heat incoming fresh air. This is particularly advantageous in colder climates, where heating costs can skyrocket during the winter months.
2. Improved Indoor Air Quality
Modern homes are built to be airtight, which can lead to poor indoor air quality due to the accumulation of pollutants, allergens, and moisture. HRVs continuously bring in fresh air, reducing the concentration of indoor contaminants and helping to maintain a healthier living environment.
3. Moisture Control
Excess humidity can lead to mold growth and structural damage in homes. By effectively managing humidity levels, HRVs help protect your home and ensure a comfortable atmosphere for its occupants.
4. Comfort
By balancing indoor temperatures and humidity levels, HRVs contribute to overall comfort in living spaces. No one likes a stuffy home, and with an HRV, you can enjoy a steady flow of fresh, conditioned air.
Why Are HRVs Important?
In an era where sustainability and health are at the forefront of public consciousness, HRVs play a vital role in:
Reducing Energy Consumption: By improving energy efficiency, HRVs contribute to lower utility bills and a reduced carbon footprint.
Enhancing Health and Well-being: With better air quality and controlled humidity, HRVs support respiratory health and overall well-being.
Adapting to Modern Building Practices: As homes become more airtight to meet energy codes, HRVs provide an effective solution for maintaining air quality without compromising energy efficiency.
Heat Recovery Ventilators (HRVs) are essential tools for achieving energy efficiency and improved indoor air quality in modern homes. Their ability to recover heat and manage humidity not only helps homeowners save money but also creates a healthier living environment. As we continue to prioritize sustainability and health, HRVs will remain a key component of smart building practices for years to come. Whether you’re renovating or building new, considering an HRV can be a significant step towards a more comfortable, efficient home.
Why you should keep your condenser coil clean.
Keeping your air conditioner in top shape is crucial for the comfort and efficiency of your home or business. One often overlooked but essential component is the condenser coil. Regular maintenance, including cleaning the condenser coil, can make a significant difference in your HVAC system's performance and longevity. Here are three compelling reasons why you should ensure your condenser coil is clean and operating at maximum efficiency.
1. Improved Energy Efficiency
A clean condenser coil is vital for maintaining optimal energy efficiency. When the coil is covered with dirt, dust, and debris, it can't effectively release heat from the refrigerant, causing the system to work harder and use more energy to achieve the desired cooling effect. This not only leads to higher energy bills but also puts unnecessary strain on the system. By keeping the condenser coil clean, you can reduce energy consumption, save money, and contribute to a more environmentally friendly operation.
2. Enhanced System Performance
The performance of your HVAC system directly impacts the comfort level of your indoor environment. A dirty condenser coil can significantly reduce the system's cooling capacity, leading to inconsistent temperatures and reduced comfort. Regular cleaning ensures that the coil can efficiently transfer heat, allowing your HVAC system to operate at peak performance. This means more consistent temperatures, quicker cooling, and an overall more comfortable living or working space.
3. Extended Equipment Lifespan
Neglecting to clean your condenser coil can lead to more significant issues over time, including system overheating and potential component failure. The additional strain on your HVAC system caused by a dirty coil can accelerate wear and tear, leading to more frequent repairs and potentially shortening the lifespan of your equipment. By investing in regular maintenance and cleaning of the condenser coil, you can prevent costly breakdowns, reduce repair expenses, and extend the life of your HVAC system, ensuring you get the most out of your investment.
Regularly cleaning your condenser coil is a small but crucial part of HVAC maintenance that can have a significant impact on energy efficiency, system performance, and equipment lifespan. By keeping your condenser coil clean, you can enjoy lower energy bills, enhanced comfort, and a more durable HVAC system. Prioritizing this simple maintenance task will pay off in the long run, providing you with a reliable and efficient heating and cooling system for years to come.
By ensuring your condenser coil is clean, you not only improve your HVAC system's efficiency and performance but also contribute to its longevity, making it a wise and cost-effective choice for any homeowner or business operator. Regular maintenance is key to maximizing your investment and maintaining a comfortable indoor environment.
Heat Pump? What is That?
As the push for energy efficiency and eco-friendly solutions grows stronger, you might have heard about heat pumps and wondered, "What exactly is a heat pump, and how does it work?" Let's break it down in simple terms.
What is a Heat Pump?
A heat pump is a versatile and efficient device that can both heat and cool your home. Unlike traditional furnaces that generate heat by burning fuel, heat pumps transfer heat from one place to another. This technology allows them to be highly energy-efficient, making them an excellent choice for both heating and cooling needs.
How Does a Heat Pump Work?
A heat pump operates on a simple principle: it moves heat rather than generating it. Here's how:
1. Heating Mode:
· Outdoor Air: Even when it’s cold outside, there’s still some heat in the air. The heat pump extracts this heat using a refrigerant.
· Heat Transfer: The refrigerant absorbs the heat and is compressed, raising its temperature.
· Indoor Release: This heated refrigerant then moves indoors and releases the heat into your home, warming it up.
2. Cooling Mode:
· Indoor Air: The heat pump extracts heat from the indoor air, cooling your home.
· Heat Discharge: The refrigerant carries this heat outside, where it is released, effectively cooling your home.
Understanding COP: Coefficient of Performance
The efficiency of a heat pump is measured by its Coefficient of Performance (COP). The COP is the ratio of the heat output to the energy input. For instance, if a heat pump has a COP of 3, it means that for every unit of electricity it consumes, it produces three units of heat.
Higher Efficiency: A higher COP means better efficiency. Most modern heat pumps have a COP ranging between 3 and 4, significantly more efficient than conventional heating methods.
Heat Pumps in Alberta: Efficiency in Lower Temperatures
You might be wondering how effective heat pumps are in colder climates like Alberta. Advances in technology have made heat pumps highly efficient even in lower temperatures. Here’s how:
1. Advanced Refrigerants: Newer heat pumps use refrigerants that perform well at low temperatures, maintaining efficiency even when it’s freezing outside.
2. Variable Speed Compressors: These compressors adjust their speed to match the heating demand, ensuring consistent performance without wasting energy.
3. Cold Climate Heat Pumps: Specialized models are designed specifically for cold climates, capable of extracting heat efficiently from extremely cold air.
Benefits of Heat Pumps
Energy Savings: By moving heat rather than generating it, heat pumps can reduce energy consumption and lower utility bills.
Environmental Impact: Heat pumps produce fewer carbon emissions compared to fossil fuel-based heating systems, making them a greener choice.
Versatility: With the ability to both heat and cool, heat pumps provide year-round comfort.
Conclusion
Heat pumps are a smart investment for homeowners looking to improve energy efficiency and reduce their carbon footprint. With their ability to operate efficiently even in the colder temperatures of Alberta, heat pumps offer a reliable solution for both heating and cooling needs. If you’re considering an upgrade to your HVAC system, a heat pump might just be the perfect choice for you.
Spotting the Difference: Legitimate HVAC Companies vs. Non Legitimate Ones
In the world of HVAC services, the difference between a legitimate company and a non-legitimate one can mean the disparity between a job well done and a potential disaster. As a homeowner or business owner seeking HVAC services, it's crucial to understand these differences to ensure you're getting quality service and value for your investment. Let's delve into the key distinctions:
Licensing and Certification:
· Legitimate HVAC Company: Holds all the necessary licenses and certifications required by local and provincial authorities. These documents ensure that technicians have undergone proper training and possess the skills to handle HVAC installations, repairs, and maintenance safely and effectively.
· Non-Legitimate Company: May lack proper licensing and certification, indicating a disregard for industry standards and regulations. Engaging with such a company puts you at risk of subpar workmanship and potential legal liabilities.
Transparency and Documentation:
· Legitimate HVAC Company: Provides clear and transparent pricing, contracts, and warranties. They ensure customers understand the scope of work, costs involved, and the terms of service agreements.
· Non-Legitimate Company: May hesitate to offer detailed pricing or written contracts, making it challenging for customers to understand what they're paying for. This lack of transparency can lead to disputes and misunderstandings down the line.
Insurance Coverage:
· Legitimate HVAC Company: Carries adequate insurance coverage, including liability insurance and worker's compensation. This protects both the company and the customer in the event of accidents, property damage, or injuries during service.
· Non-Legitimate Company: Might operate without insurance coverage, leaving customers vulnerable to financial risks in case of accidents or property damage caused by the company's negligence.
Quality of Workmanship:
· Legitimate HVAC Company: Strives for excellence in every job, using high-quality materials, adhering to industry best practices, and employing skilled technicians. Their work is backed by warranties and guarantees, offering peace of mind to customers.
· Non-Legitimate Company: May cut corners, use inferior materials, or employ inexperienced technicians to save costs. This compromises the quality and durability of the work performed, leading to frequent breakdowns and costly repairs in the future.
Commitment to Customer Satisfaction:
· Legitimate HVAC Company: Values customer satisfaction and prioritizes long-term relationships over short-term gains. They listen to customer concerns, address issues promptly, and stand behind their work with responsive customer support.
· Non-Legitimate Company: Might prioritize profit over customer satisfaction, resulting in poor service, neglect of customer complaints, or difficulty in obtaining follow-up support after the initial service.
Choosing a legitimate HVAC company is paramount for ensuring the safety, reliability, and efficiency of your heating, ventilation, and air conditioning systems. By understanding the differences outlined above and conducting thorough research before hiring an HVAC contractor, you can safeguard your investment and enjoy peace of mind knowing that your HVAC needs are in capable hands.
Making the Right Call: Repairing or Replacing Your HVAC System
Your HVAC (Heating, Ventilation, and Air Conditioning) system is a critical component of your home or business, ensuring comfort and indoor air quality year-round. However, like any mechanical system, it will eventually require attention. The big question many homeowners and business owners face is whether to repair the existing system or invest in a replacement. In this guide, we'll explore the factors to consider when making this important decision.
1. Age of the System: One of the primary considerations when deciding between repairing and replacing your HVAC system is its age. Most systems have a lifespan of around 10-15 years, depending on maintenance and usage. If your system is approaching or exceeding this age range, it may be more cost-effective in the long run to replace it rather than continue to invest in repairs.
2. Frequency and Cost of Repairs: Take a close look at your recent repair history and costs. If you find yourself calling the HVAC technician frequently for repairs, or if the cost of the repairs is becoming substantial, it may be a sign that your system is nearing the end of its life. In such cases, investing in a new, more efficient system can save you money on future repair bills and energy costs.
3. Energy Efficiency: Older HVAC systems tend to be less energy-efficient compared to newer models. If you notice a significant increase in your energy bills or if your system struggles to maintain comfortable temperatures, it may be a sign that it's time for an upgrade. Newer systems are designed to be more energy-efficient, which can lead to lower utility bills and reduced environmental impact.
4. Comfort and Performance: Consider how well your current HVAC system is performing in terms of comfort and air quality. If you're experiencing uneven heating or cooling, excessive humidity, or poor indoor air quality, it may be a sign that your system is no longer capable of meeting your needs. Upgrading to a new system can improve comfort levels and provide better air filtration.
5. Long-Term Cost Analysis: While the upfront cost of replacing your HVAC system may seem daunting, it's essential to consider the long-term cost implications. Newer systems typically come with warranties and may qualify for rebates or tax incentives, which can help offset the initial investment. Additionally, factor in potential savings on energy bills and reduced repair costs over the lifespan of the new system.
Deciding whether to repair or replace your HVAC system is a significant decision that requires careful consideration of various factors. While repairing may seem like a cost-effective solution in the short term, it's essential to weigh the long-term benefits of investing in a new, more efficient system. Consulting with a qualified HVAC professional can help you assess your options and make an informed decision that meets your comfort and budgetary needs. Remember, investing in your HVAC system is an investment in the comfort and well-being of your home or business.
Understanding Residential Air Filters: Addressing Odors, Forest Fire Smoke, and Pet Dander with Appropriate MERV Ratings
In the realm of residential HVAC systems, ensuring indoor air quality is paramount for the health and comfort of occupants. One of the key components in achieving this is selecting the right air filters. In this blog, we will delve into the differences and requirements of filters for residential applications, particularly focusing on their efficacy in addressing odors, forest fire smoke, and pet dander, while also considering the appropriate Minimum Efficiency Reporting Value (MERV) ratings.
Types of Filters: Before discussing specific requirements, let’s briefly touch upon the different types of filters commonly used in residential HVAC systems:
1. Fiberglass Filters: These are the most basic and inexpensive option. While they capture larger particles, they are not effective at filtering out smaller particles or odors. Recommended MERV Rating: 1-4.
2. Pleated Filters: Offering better filtration than fiberglass filters, pleated filters are made of polyester or cotton and are capable of trapping smaller particles. However, they may still be inadequate for eliminating odors or smoke particles. Recommended MERV Rating: 5-8.
3. High-Efficiency Particulate Air (HEPA) Filters: HEPA filters are highly effective at capturing tiny particles, including pet dander and smoke particles. However, they may not necessarily eliminate odors unless combined with additional filtration mechanisms. Recommended MERV Rating: 17-20.
4. Activated Carbon Filters: These filters excel at removing odors, gases, and volatile organic compounds (VOCs) due to their porous structure. They are particularly useful in combating household odors and smoke particles. Recommended MERV Rating: N/A (MERV ratings are not typically assigned to activated carbon filters).
Addressing Odors: For residential applications where odors are a concern, such as cooking smells or household odors, activated carbon filters are indispensable. These filters contain a layer of activated carbon that adsorbs odorous molecules, effectively neutralizing unpleasant smells and improving indoor air quality. When selecting filters for odor removal, opt for those specifically designed with activated carbon or incorporate activated carbon as an additional layer within the filter.
Combatting Forest Fire Smoke: In regions prone to forest fires or experiencing poor air quality due to wildfires, mitigating the infiltration of smoke particles into indoor spaces becomes crucial. HEPA filters are highly recommended in such scenarios. With their ability to capture fine particles, including those present in smoke, HEPA filters can significantly reduce the amount of harmful pollutants entering the home. Additionally, combining HEPA filters with activated carbon filters can provide comprehensive protection against both particulate matter and odorous compounds present in wildfire smoke.
Managing Pet Dander: For households with pets, especially those with allergies or sensitivities to pet dander, effective filtration is essential. HEPA filters are once again the preferred choice due to their ability to capture microscopic particles, including pet dander, fur, and other allergens. Regularly replacing or cleaning HEPA filters is crucial to maintain optimal performance and prevent the buildup of allergens within the home. Additionally, incorporating activated carbon filters can help eliminate pet odors, further enhancing indoor air quality and comfort for occupants.
Selecting the right air filters for residential HVAC systems involves considering various factors, including the specific air quality concerns present in the home and the appropriate MERV ratings. Whether addressing odors, forest fire smoke, or pet dander, choosing filters tailored to the unique requirements of each situation is essential for achieving clean and healthy indoor air. By understanding the differences and capabilities of different filter types and their associated MERV ratings, homeowners can make informed decisions to safeguard their indoor environment and promote well-being for all occupants.
Maximizing Efficiency: Role of Clean A/C Coils in Energy Conservation
In the realm of HVAC maintenance, one often overlooked yet fundamentally crucial aspect is the cleanliness of air conditioning coils. While it might seem like a minor detail in the grand scheme of cooling systems, maintaining clean A/C coils is paramount for optimizing energy efficiency and reducing operational costs. In this blog, we delve into the significance of clean coils in the pursuit of energy conservation and enhanced HVAC performance.
Understanding A/C Coils: The Heart of Cooling Systems
Air conditioning coils play a pivotal role in the heat transfer process within HVAC systems. Typically, air conditioning systems comprise two types of coils: the evaporator coil and the condenser coil. The evaporator coil absorbs heat from indoor air, while the condenser coil releases heat to the outdoor environment. This intricate exchange of heat is essential for cooling indoor spaces effectively.
The Impact of Dirty Coils on Energy Efficiency
Over time, A/C coils accumulate dirt, dust, and other debris from the surrounding environment. This buildup forms a layer of grime that impedes the heat transfer process, thereby compromising the efficiency of the cooling system. Several consequences arise from dirty coils, including:
1. Reduced Heat Transfer Efficiency: Dirt accumulation insulates the coils, hindering the transfer of heat between the refrigerant and the surrounding air. As a result, the system requires more energy to achieve the desired cooling effect, leading to increased energy consumption and higher utility bills.
2. Decreased Cooling Capacity: Dirty coils impair the airflow through the system, causing uneven cooling and potentially overworking the compressor. This can lead to diminished cooling capacity and decreased comfort levels indoors.
3. Accelerated Wear and Tear: The added strain on the HVAC system due to dirty coils can accelerate wear and tear on components, leading to frequent breakdowns, premature system failure, and costly repairs.
Dirty evaporator coil.
The Importance of Regular Coil Cleaning
To mitigate the adverse effects of dirty coils and maximize energy efficiency, regular maintenance and cleaning are imperative. Here's why:
1. Optimized Performance: By keeping A/C coils clean, heat transfer efficiency is optimized, allowing the system to operate at peak performance levels. This results in lower energy consumption, reduced operational costs, and improved comfort for building occupants.
2. Extended System Lifespan: Routine coil cleaning helps prevent excessive strain on HVAC components, prolonging the lifespan of the system and minimizing the need for costly repairs or premature replacements.
3. Enhanced Indoor Air Quality: Clean coils contribute to better indoor air quality by preventing the circulation of airborne pollutants and allergens that may accumulate on dirty surfaces. This promotes a healthier and more comfortable indoor environment for occupants.
Clean evaporator coil
Prioritize Coil Cleaning for Energy Efficiency
In conclusion, the importance of keeping A/C coils clean cannot be overstated when it comes to energy conservation and HVAC performance optimization. By incorporating regular coil cleaning into your maintenance routine, you can reap the benefits of improved energy efficiency, extended system lifespan, and enhanced indoor comfort. Don't overlook this critical aspect of HVAC maintenance—invest in clean coils for a more sustainable and cost-effective cooling solution.
The Crucial Role of Filtration in Your HVAC System: A Small Investment with Big Payoffs
In the intricate dance of components that make up your HVAC system, one often underestimated yet essential player is the unassuming air filter. Despite its modest appearance, the filter serves as the first line of defense against airborne particles, ensuring that your indoor air remains clean and your HVAC system operates smoothly. In this blog, we'll explore why filtration is paramount in an HVAC system and why regular filter replacement is not just a good idea, but a must for both the health of your space and the longevity of your furnace.
The Guardian at the Gate
Imagine your HVAC system as a vigilant guardian tasked with maintaining a comfortable indoor environment. Now, picture the air filter as the sentinel stationed at the gates, intercepting dust, pollen, pet dander, mold spores, and other contaminants before they infiltrate your living or working space. Without this barrier, these airborne nuisances would circulate freely, contributing to poor indoor air quality and potentially exacerbating respiratory issues and allergies among occupants.
Unleashing Efficiency
Beyond safeguarding indoor air quality, proper filtration plays a pivotal role in the efficiency of your HVAC system. A clean filter allows air to flow freely through the system, minimizing strain on components such as the blower motor and evaporator coil. Conversely, a clogged filter impedes airflow, forcing the system to work harder to achieve desired temperature levels. This increased workload not only consumes more energy but also accelerates wear and tear on vital components, leading to more frequent breakdowns and costly repairs.
Comparison between a clean filter and a dirty filter.
The Cost-Effective Solution
Now, let's address the elephant in the room: the perceived hassle and expense of filter replacement. Contrary to popular belief, replacing your filter is neither arduous nor costly—in fact, it's one of the simplest and most cost-effective maintenance tasks you can perform for your HVAC system. Most filters are designed for easy installation, requiring only a few minutes of your time and minimal effort. And when you consider the potential savings in energy costs and repair bills, the investment in regular filter replacement pales in comparison.
A Healthier Environment, a Longer Lifespan
Regular filter replacement isn't just about preserving indoor air quality and optimizing HVAC efficiency—it's also about safeguarding the health of your space and prolonging the life of your furnace. By ensuring that your HVAC system operates smoothly and efficiently, clean filters help prevent the buildup of dirt and debris that can compromise system performance and lead to premature failure. In essence, a small investment in filter replacement today can yield significant returns in terms of occupant health and system longevity tomorrow.
Conclusion
In the grand scheme of HVAC maintenance, the importance of filtration cannot be overstated. By serving as the first line of defense against airborne contaminants and promoting optimal system performance, clean filters play a vital role in maintaining a healthy indoor environment and extending the lifespan of your HVAC system. So, the next time you're tempted to overlook your filter replacement schedule, remember the profound impact this small yet crucial task can have on the comfort, health, and efficiency of your living or working space. It's a small investment with big payoffs—one that can save you hundreds of dollars down the road.
The Crucial Role of Regular HVAC Maintenance
It all begins with an idea.
In the world of heating, ventilation, and air conditioning (HVAC), the importance of regular maintenance cannot be overstated. Whether you are a homeowner or a business owner, ensuring your HVAC equipment is well-maintained is not just about comfort; it's a strategic investment that pays off in the long run. In this blog post, we'll delve into the significance of maintaining your HVAC equipment, emphasizing how cleanliness and proactive care can extend the lifespan of your system while preventing minor issues from escalating into major problems.
Dirty boiler heat exchanger.
1. Enhanced Longevity: One of the primary benefits of routine HVAC maintenance is the extension of equipment lifespan. As a homeowner or business owner in the HVAC service industry, you understand that these systems are substantial investments. Regular cleaning and inspections can help identify potential issues before they become critical, allowing you to address them promptly. This proactive approach not only saves you money on premature replacements but also ensures your HVAC equipment operates at peak efficiency for an extended period.
2. Optimized Performance: Clean HVAC systems operate more efficiently, providing better heating and cooling performance. When dust, dirt, and debris accumulate within the system, it forces the equipment to work harder to maintain the desired temperature. This not only leads to higher energy consumption but also places unnecessary stress on components, resulting in more frequent breakdowns. By scheduling regular maintenance, you can keep your HVAC system running smoothly, ensuring optimal performance and energy efficiency.
3. Cost Savings in the Long Run: As a savvy homeowner or business owner, you understand the impact of operational costs on your bottom line. Neglecting HVAC maintenance might seem like a cost-saving measure in the short term, but it often leads to higher expenses in the long run. Small issues left unattended can escalate, resulting in major repairs or even the need for a complete system replacement. By investing in regular maintenance, you can identify and address minor problems before they evolve into costly emergencies, ultimately saving your wallet or business from unexpected financial burdens.
4. Improved Indoor Air Quality: For both residential and commercial spaces, maintaining good indoor air quality is essential. A well-maintained HVAC system helps filter and circulate clean air, reducing the presence of allergens, dust, and pollutants. This is particularly important in commercial settings where the health and well-being of employees and customers contribute to overall productivity and satisfaction.
Heat exchanger after cleaning.
In the world of HVAC, the adage "an ounce of prevention is worth a pound of cure" holds true. Regular maintenance is not just a routine task; it's a strategic investment in the longevity, performance, and efficiency of your HVAC equipment. As a homeowner or business owner in Alberta, where temperature extremes are not uncommon, prioritizing the care of your HVAC system is a business-savvy decision that pays dividends over time. Don't wait for problems to arise; schedule regular maintenance and enjoy the comfort, cost savings, and peace of mind that come with a well-maintained HVAC system.