If you’re in the process of building a home and want to keep it filled with fresh, healthy air year-round, then you have an important decision to make – which ventilation system to add to your HVAC package.
The most effective ventilation options available for residential homes are HRVs and ERVs. In order to choose the right one for your home, it’s important to understand the differences between the two products.
Both HRV’s (such as models produced by SummerAire Mfg) and ERV’s (like those produced by Solar & Palau – S&P) perform the same basic function in your home, essentially removing stale indoor air and replacing it with fresh outdoor air. Both products include exhaust and supply fans, along with a plate-type energy transfer cell/core that both the exhaust and supply air streams pass through. The outgoing air stream tempers the incoming air stream in a process referred to as an “energy transfer”.
In HRVs, the heat in the stale exhaust air is used to raise the temperature of the incoming outdoor air as it enters your home during the heating season. This process reduces the energy used by your home’s heating system to raise the outside air up to the temperature set point on your home’s thermostat. HRV cells are made out of non-permeable materials such as aluminum or a plastic composite which doesn’t allow any cross contamination of the exhaust or incoming air streams.
An ERV, also known as an enthalpy recovery ventilator, differs from an HRV because the material the cell is made out of is permeable (often a paper composite), allowing some of the moisture in the exhaust air to transfer into the incoming outdoor air which is often moisture deprived during the heating season in cold climates.
In more technical terms, the more humid indoor air equalizes the humidity of the drier air in order to make the humidity level in a home more comfortable and healthy (the HVAC industry recommends maintaining humidity levels in living spaces between 35-45%. In the cooling season, the ERV will reverse the transfer to remove humidity from the incoming fresh air before it enters a home. This saves energy by reducing the load on your air conditioning system and/or dehumidifier.
Both HRVs and ERVs help reduce the stress on your HVAC system compared to other ventilation methods. Both options are sound, and the decision really comes down to your climate, lifestyle, and home design. A general rule of thumb is an HRV is more effective in cold climates and an ERV is better suited for hot humid climates that require considerably more cooling than heating.
Since outdoor air during the heating season is most often considerably drier than a home’s indoor air, running an HRV can significantly reduce humidity levels, thus requiring a humidifier to maintain the 35-35% humidity in a home.
On the other hand, cold temperatures are a concern with ERV’s because the moisture in the cell will freeze at what is referred to as the dew point (frost point) which can occur in many cold climates – the colder the winter design temperature is for a specific area, the more likely an ERV cell will be exposed to freeze up; a condition where ice forms within the cell and air flow is either reduced or completely inhibited from passing through the device. Most HRV’s have built-in defrost systems which keep their cells from freezing up while functioning cold climates.
No matter which system you choose, installing one or the other will help reduce energy consumption and costs while ventilating your home. Both types recommend a continually running fan, but the amount of energy saved is much greater than what it takes to keep the fan running. Energy efficiencies for both types can range from the mid-55’s to over 90%, though the most efficient units come at a much higher cost. However, when you factor the value of energy savings over the unit’s full life cycle, choosing the most efficient model can often make it a financially and ecologically sound investment.
In the end, there is not one right choice. The choice between a Summeraire HRV and S&P ERV is not as important as the decision to incorporate mechanical ventilation into your home. The leaky houses of the past simply cannot compare with the airtight house designs of today.
Current homes entrap airborne contaminants like bacteria, allergens, viruses, mold spores and toxins (such as formaldehyde gasses from glues used in many household materials). HRV or ERV ventilation systems help to reduce the concentrations of these contaminants in an effective and efficient manner. Since your family’s health is likely at the top of your priority list, don’t overlook the important role that proper ventilation in your home can play.
Electric duct heaters are a convenient, affordable and effective way to provide heat to a room or ventilation duct system. Professional HVAC contractors have used these devices in residential, commercial and industrial HVAC systems for many years.
The main idea behind heating with an electric duct heater is adding heat to the air inside the duct in an efficient manner. Electric duct heaters can be used in a broad range of applications, some of the most popular of which are:
When choosing an electric duct heater for your home or workplace, you’ll want to keep the specific application in mind when deciding the model you need.
Electric Duct Heaters typically use one of two types of heating elements:
Electric duct heaters are either designed to be staged on/off or modulating. Of these two, modulation is the best way to control duct temperatures.
On/off design is typically chosen when a duct heater is controlled by a wall thermostat and used to maintain temperature in a room. Modulation is best when a heater is used to maintain a set temperature in the duct and is controlled by a duct thermostat. Modulating control uses just the right amount of heat to maintain the temperature set by the duct thermostat, saving energy and improving comfort.
Duct thermostats can control temperatures using electric, electronic and pneumatic controllers. Large systems may even benefit from a sophisticated Direct Digital Control (DDC) system. Electric duct heaters are designed to interface with any of these options and are available in virtually any size, power handling and voltage.
Both open-coil and tubular heating elements require air flow to transfer the heat from the elements to the air in the duct. If the air flow stops for any reason, temperature in the duct can rise to dangerous levels.
This is the reason companies like Thermolec install automatic thermal cut-off features as well as manual resetting thermal cut-offs. Air flow can be stifled by obstacles and debris without warning, making redundant safety features like these critically important.
For a standard HVAC system, selecting a heater is straightforward once the basics of electric duct heater operation are understood. It comes down to three steps:
With this information in hand, you’ll be ready to choose between the various affordable, high-performance electric duct heaters on the market.
If you have a high-powered, commercial-quality cooktop installed in your kitchen, chances are you also have a makeup air unit installed in your home. This device compensates for the amount of air being pushed out of your kitchen’s extractor and breathes fresh, room-temperature air in from outside. Makeup air units are typically automatic—unless you had yours recently installed, you may not even know you have one, but you’ll notice if it breaks down.
If your cooktop comes with a large extractor hood that sweeps out odors and contaminants from your home, your makeup air system is what’s responsible for replacing the lost air. Without it, your home would be depressurized and the kitchen hood would soon be unable to push the air out. The fumes would collect inside your house—creating a dangerous environment for you and your family.
Fortunately, makeup air units are built to last, and if you take care to have yours regularly inspected you can catch any problematic developments before they seriously affect the device’s ability to function safely. Robert Tinsley of HPAC Engineering suggests biannual inspections for the best results. Have a certified HVAC technician examine the following:
The filters, fan wheels, burners and orifices of the device generally only need to be cleaned. They will work perfectly as long as they are not covered or clogged with debris.
It can be helpful to think of your makeup air unit as just one part of an overall kitchen ventilation system. If the unit is working perfectly but the kitchen extractor hood is filled with gunk and debris, it stands to reason that you’ll experience some unexpected results.
Cooking hoods are simple to clean, requiring no more than elbow grease and a good cleaning solvent. Most contain some kind of filter that requires regular replacement—make sure that it isn’t obstructed, and consult Cleanipedia’s guide for more specifics on keeping it grease-free. With both these appliances in good shape, your home’s interior air pressure should remain in perfect equilibrium.
Heating your home with a heat pump is energy efficient and cost-effective. When dry indoor air becomes a problem in winter, however, you’re likely to find that the central humidifiers that work just fine with fossil-fuel-fired furnaces aren’t as effective when used in conjunction with a heat pump. Fortunately, a steam humidifier may be the solution to the problem.
At best, dry indoor air is a nuisance. It can make your skin itchy, your lips dry and cracked, and your throat irritated. It can even make your nose bleed.
For some, those minor irritations can lead to even more serious problems. When dry air irritates your throat and your nasal passages, you’re more susceptible to respiratory illnesses such as cold and flu, sinus infections, and reactions to allergens. Asthma sufferers may experience more frequent or more severe asthma attacks when the air is dry, too.
Dry air isn’t kind to your home and the things in it, either. Low humidity can cause wood floors and finishes to dry out, shrink, and crack; wood furniture is vulnerable to damage caused by dry air, as well.
Perhaps worst of all, we’ve all experienced the inconvenient—and sometimes painful—build up of static electricity that occurs when dry air helps surfaces hold their static charges.
Many home heating systems incorporate a humidifier that works by bypassing some of the warm air generated by the furnace through an evaporator pad that’s saturated with water. As the warm air flows across the pad, it picks up some of the moisture from the pad, and that moisture is distributed through the home’s heating ducts. Over time, the added moisture increases the relative humidity of the air throughout the home.
Steam humidifiers, such as those manufactured by Thermolec, take an active approach to raising your home’s humidity. In these systems, a sensor called a humidistat recognizes when the air in your home is too dry, and when the humidity drops below a specified level, the humidistat triggers the production of high-temperature steam in a reservoir attached to the system. That steam is then mixed with the heating system’s warm air and is sent throughout the house, raising the humidity of the indoor air.
Steam humidifiers use less water than bypass humidifiers. Bypass humidifiers often use as much as 15 gallons of water to produce one gallon of water vapor, while steam humidifiers can produce almost one gallon of vapor for every gallon of water used.
Steam humidifiers also typically require less maintenance than bypass humidifiers, whose evaporator pads need to be replaced at least once a year. Thermolec’s Acu-Steam system is designed to operate for more than 10 years without needing a replacement canister or heating element.
Steam humidifiers are especially advantageous in homes heated by heat pumps. Heat pumps typically produce warm air with a lower temperature than that produced by gas- or oil-fueled furnaces, and bypass humidifiers don’t work as well when the air passing over the evaporator pad isn’t warm enough.
Steam humidifiers generate steam using their own heat source, so they don’t rely on the temperature of the heating system’s air to produce moisture. As a result, they’re able to consistently introduce more moisture throughout your home when working in conjunction with the relatively low-temperature air put out by the heat pump.
Working in coordination with one another, a heat pump and a steam humidifier prevent dry winter indoor air from making your home uncomfortable and unhealthy, and they do it in the most energy-efficient, cost-effective, hassle-free way possible.
Thermolec Acu-Steam humidifiers are the most dependable and easiest tomaintain steam humidifiers on the market.Acu-Steam will tolerate a variety ofwater conditions, it’s unique design includes self-cleaning elements enclosedin a quick release stainless steel tank, eliminating the need to buy costlyreplacement tanks.Element and tank carry a 10 year warranty. A pressureswitch is included as a standard feature, assuring that steam is not introducedinto the ductwork if the system fan has failed. Three sizes cover from 13to 37gallons per day.
The Thermo-Air (TER) and Thermo-Zone (ZON) electric duct heaters are unique to Thermolec. Both are available with 6” – 12” round duct connections and up to 12 kW of electric heat in single phase power. Both units come with an electronic airflow sensor and duct temperature sensor. The TER has a duct stat to control temperature in the duct. The ZON comes with a wall stat to control room temperature. Both units are fully modulating so only the right amount of energy is used to maintain temperature.
Thermolec is one of the top three custom duct heater manufacturers in North America. They can build any size and any configuration of electric duct heater. They specialize in open coil element heaters and have the shortest lead times in the industry. Thermolec’s advanced electronics give designers the superior option of modulating control at a staged heater price.
The FER from Thermolec provides make-up air in 100, 300 and 600 cfm increments with electric heat for up to 100°F temperature rise. All FER units include a washable filter, back-draft damper, speed controllable fan and modulating electric heater. A current sensing relay is included to automatically start the MUA fan when the exhaust fan is energized.
The NER from Thermolec provides make-up air from 600 to 2,500 cfm with electric heat for up to 100°F temperature rise. NER units include a washable filter, back-draft damper, modulating electric heater and dry contact to start a remote fan. A current sensing relay is included to automatically start the MUA system when the exhaust fan is energized. EP Sales includes the remote fan and speed controller as part of an NER MUA package.
The HPX Modulating Plenum Heater is advanced technology ideal for dual-fuel/ hybrid HVAC systems. Hybrid systems that utilize an air source heat pump with an HPX plenum heater can provide up to 50% savings on annual heating costs compared to conventional forced air heating systems. The HPX plenum heater maximizes an air source heat pump’s efficiency and savings by modulating it’s output and providing additional btu’s as needed on colder days, allowing the heat pump to operate even below the comfort balance point. HPX works with any air source heat pump and/or gas furnace.