AC and Heating Tip from AC Express
Heat Recovery Ventilators
There are a lot of forces to balance when it comes to creating the perfect environment in your house. You have to consider and control temperature, humidity, circulation, ventilation, insulation and air quality. And the machines and materials we use to alter and control these different aspects of the air in our homes sometimes work against one another. That means getting the air in your home, the atmosphere in which you’ll spend most of your time, to its ideal conditions is a bit of balancing act. One aspect of this that is particularly difficult to balance is the battle between insulation, ventilation, and heating in Austin.
As we get better and better at keeping pests, allergens, and outside air from contaminating our indoor air, we simultaneously find ourselves with less and less natural ventilation and circulation of air within our homes. It’s a bit of a tradeoff. Insulation gets better but ventilation gets worse. And as much as preventing outside air from getting in is good for decreasing certain air quality reducing factors such as pollen and other allergens, the ventilation and circulation of air is very crucial to creating a high quality air environment. That’s where heat recovery ventilators come. The purpose of these appliances is to make sure that no matter how well insulated your house is you’re still getting proper ventilation without any loss of heat from your heater. Read on to learn more about this device and its benefits.
Why Use a Heat Recovery Ventilator?
Before we get into exactly how heat recovery ventilators work let’s discuss why they were a necessary invention in the first place so you can understand their place in the modern world of heating. There was an era in the history of modern heating in which homes were not built as tightly sealed as they were today. Home builders before the 70s didn’t put a lot of emphasis on immaculate insulation. That’s why the stereotype of the old house with all the drafts is so prevalent. There were more gaps and less thought put towards keeping the exchange of air between indoors and outdoors to a minimum.
This meant that it was harder to keep the rooms in the house warm in the winter but that didn’t matter as much because it didn’t cost as much to run the heater. So people happily just cranked up the thermostat as their method for battling the loss of heat due to poor insulation. The problem is eventually heating costs did rise and as they did it suddenly became much more important to people to increase insulation. Houses became more air sealed and tightly fitted and as a result drafts were eliminated and the exchange of air between the inside and outside of homes lessoned. This made it easier to heat and cool the home but it had a side effect. It turned out that those drafts actually doubled as a form of natural ventilation that kept the air circulated and fresh. Without it, other problems started to emerge like an increase in mold and mildew growth.
Life inside today's tight home generates both moisture and pollutants. The moisture comes from cooking, washing, showers and breathing. At excessive levels, moisture condenses on windows and can cause structural deterioration. Areas of excessive moisture are also breeding grounds for mold, mildew, fungi, dust mites and bacteria. You know you have a problem if you find moisture collecting on your windows, or if you notice black spots on walls. These unsightly spots indicate mildew growth. Mold spores and dust easily become airborne and circulate freely throughout the house, possibly causing a range of symptoms and allergic reactions.
In addition to excessive moisture and biological contaminants, appliances that utilize combustion have the potential for allowing gases, including carbon monoxide, and other pollutants to escape into the air. Some common sources may include gas ranges and water heaters, unvented space heaters, leaky chimneys and wood-burning appliances. Even breathing can add to the problem when carbon dioxide reaches excessive levels, creating stale air. And that's not all that gets into the air. If your home is new, the very products it's made of can give off gases that are less than agreeable to your comfort and good health, and in many areas of the country there's a concern about radon seeping from the ground.
How Do They Work?
So heat recovery ventilators solve the conundrum of wanting a house that’s both well insulated and well ventilated. They promote healthy indoor air by keeping the air fresh without letting the heat escape. It’s a great compromise between efficiency and quality. But how exactly do they work?
Heat recovery ventilators, or HRVs for short, consist of two ventilation ducts running next to one another passing between the inside and the outside of a house. One carries cool, fresh air in; the other carries moist, stale air out. The most important and defining feature is that the airstreams run through a device called a heat exchanger that allows the outgoing air to pass most of its heat to the incoming air without the two airstreams actually mixing together. Usually there's a fan or blower in each duct that can be turned up or down either manually or automatically depending on the temperature and humidity levels. The incoming air supply may also have a bypass fitted to it so that on summer days when it's cooler outside than in, cold outside air can be channeled straight into the home without meeting outgoing air (much like opening a sash window).
It’s like a crisscross effect. Cold but fresh outside air is pumped into the house while simultaneously being warmed by the hot but stale air being pumped out. The concept is simple but effective. Usually the ducts carrying air out of the home are situated so that they pull air from areas in the house that typically generate the most moisture such as the bathrooms and the kitchen. Heat-recovery ventilators can be retrofitted in homes with ducted heating systems. Most contain air filters, some have dehumidifiers built in.
Pros and Cons of Heat Recovery Ventilators
The pros of heat recovery ventilators should be fairly obvious by now. They harmoniously deal with three different aspects of your home’s air, temperature, ventilation, and humidity. They deal with the problem of low ventilation and poor circulation caused by good insulation which solves the conundrum caused by a lack of fresh air. No fresh air means a build up of moisture and the growth of mold and mildew which will end with an indoor environment that may be warm but is also going to be unhealthy. Heat recovery ventilators continuously exchange that air with fresh and dryer air from outside while simultaneously exchanging that heat so that you don’t lose out on efficiency from your heater’s hard work. In the end you’ve got cleaner, fresher, less humid air that still retains its warmth in the winter and its coolness in the summer.
It’s not all sunshine and rainbows though. You have to consider that this is an investment for your health and air quality and as such won’t necessarily come cheap. Heat recovery ventilators are expensive to install initially (several thousand dollars is typical) and they're not guaranteed to pay for themselves. Your typical annual savings might be a few hundred dollars. You'll see most benefit in extreme climates: where the difference between the outdoor and indoor temperatures is greatest in summer, winter, or both. In milder climates, the benefits are much reduced and may, in some cases, be nonexistent. Don't forget that a typical HRV has a couple of small, electric fan blowers in it and costs money to run. You’ll only save money overall if you can recoup the installation costs and generate enough savings to cover the running costs as well. If you're environmentally minded and money is less of an issue, saving more energy in heat recovery than you use in the system itself is obviously the thing you need to focus on. If you're using a heat recover ventilator in particularly cold climates, you'll need slightly more sophisticated equipment to stop the system from freezing up but that’s not so much of a problem here in Austin. HRVs also need regular maintenance, with filters that typically need cleaning or replacing every six to twelve months.
You also have to consider that a heat recovery ventilator isn’t your only option. There is also the possibility of using an exhaust only ventilator. This typically comes in the form of an exhaust fan placed in the bathrooms of the house that works as a one way air exchange system, putting stale air out while new air enters only passively. Exhaust-only ventilation systems use one or more high-quality bathroom exhaust fans controlled by a timer. They don’t run all the time and thus typically use less energy.
Heat Recovery Ventilators and Heating Repair in Austin
Consider the heat recovery ventilator. It’s an answer to the question of how do we balance good insulation and good ventilation. As our houses get more expertly sealed tight and insulated we have to think about how we’re going to get fresh air continually into our houses. A heat recovery ventilator is one way to do that. They’re not perfect solutions to the problem but they do reduce moisture without losing heat, making them worth the consideration when you’re looking for a ventilation solution.
If you’re ever in need of heater repair in Austin you’ll want the best of the best on your side. The expert technicians at AC Express are proficient working on any type, brand, and model of heater you might have. We’re an Austin heater repair company operating in and around Austin, from Buda and Kyle to Taylor and Round Rock. Call today if you need help with you Austin heating.
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