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"I have had Custom Vac install two air conditioners in my home. I have had them service my furnace when required and just recently had them install a new Trane furnace in my home. I picked the Trane because Custom Vac's employee pointed out the benefits of this brand with regards to the size and layout of my home. Custom Vac did an excellent job and checked extras such as the air conditioner, humidifier, new chimney liner, etc. Custom Vac also offers 24 hour emergency service and I had occasionally used this service with my old furnace. I will continue using Custom Vac if and when I need help. I would not fail to recommend them for any job they undertook."
Henry C. Turner

There are so many intake and exhaust ducts in buildings today that it's mind boggling as to what they do and where they are located. Often homeowners call requesting a fresh air intake be installed to the furnace, when what they really want is a combustion air intake installed in order to ensure a safe operating appliance. In addition, the introduction of ventilation air can be done efficiently and effectively with new equipment such as the Venmar 1.5 EKO that has been designed to exceed the Federal Government Energy Efficiency standard for both July 2010 and July 2012. This means that you can achieve the best indoor air quality while at the same time keeping your energy bills low. With the introduction of make-up air, combustion air, fresh air, etc., we felt we should help clear the air.

Combustion Air

Combustion air is the air required to provide adequate oxygen for fuel burning appliances in the building. The term combustion air refers to the total air requirements of a fuel-burning appliance. This is air to both, support the combustion process and to provide chimney draft (dilution air). This combustion air intake should be located within 1 ft. (300 mm) above, and 2’ (600 mm) horizontally from the burner level of the appliance having the greatest largest input (heating capacity). Note: Be sure to check local codes.

Exhaust Air

Exhaust air is the air removed from a space and not reused. This includes air from kitchen and bathroom fans, clothes dryers, central vacuums, etc. which mechanically expelled air to the outdoors. The term "exhaust" may be prefixed to describe its source (for example, dryer exhaust, kitchen exhaust, central vacuum exhaust). Exhaust air terminations are located almost anywhere that will not result in this polluted air being drawn or allowed back into the building. Exhaust air, is always considered to be contaminated.

Make-up air

Make-up air is outdoor air supplied to replace exhaust air. Make-up air may enter the house by infiltration, through a make-up air duct, through a supply fan etc. It does not include air entering the house as combustion air or to replace exfiltration air.

Relief Air

Relief air mechanically removed, passively exiting, or exfiltrating from the building to reduce mechanically induced pressurization (opposite of make-up air)

Outdoor Air

Commonly called fresh air, outdoor air from the external atmosphere (outdoors), not previously circulated in the building. It is usually less contaminated than indoor air, passive air in nature, and normally connected to the return air of the furnace.

Ventilation Air

Ventilation air is outdoor air intentionally supplied by mechanical means to a conditioned space.

Ensuring that your home or building has adequate ventilation is a serious consideration, one that must be dealt with by professionals who have the knowledge to put together a system that will ensure comfort and safety. Custom Vac has the trained and certified staff to meet your needs.

Taking Control of Indoor Air Quality (IAQ)

As our homes, schools and workplaces become "tighter," due to a quest for higher energy-efficiency, the quality of our indoor air has suffered. In Canada, where the average person spends a minimum of 90% of the time indoors (higher in winter months), more homeowners and building owners are looking for solutions to poor IAQ. Custom Vac Limited is in the ideal position to educate building owners, and to provide you with those solutions.

Be aware, however, that because each individual has a different tolerance to irritants, not everyone will show adverse symptoms. So, be thorough in your research and be certain to choose a contractor who is knowledgeable in IAQ.

There are physical clues, which you can look for to determine a building's air quality, such as mildew in bathrooms or kitchens and paint flaking around windowsills. A build up of moisture in a home or building is usually due to a lack of ventilation and poor air circulation, adding to indoor air problems.

Identifying Pollutant Sources

After determining that a home or building has an IAQ problem, the next step is to identify the source(s). There are many possibilities to consider. Start with open containers of solvent or paint, and regular household cleaners. Other major causes of poor IAQ include:

  • dust

  • wood finishes

  • synthetic materials used in the construction of furniture and cupboards (e.g. presswood)

  • tobacco products

  • carpeting and under padding

  • newspapers, books and other items stored in a damp and musty basement

  • damp or wet flooring materials

  • pets

Also, consider fuel-fired appliances including wood burning stoves, fireplaces, space heaters or even a hot water heater. In offices, major contributors to the problem could be many of the items previously mentioned along with laser printers, photocopiers, and in some cases asbestos-containing insulation or ceiling or floor tiles.

Offering Solutions

In most cases the best way to improve indoor air quality is to eliminate individual sources of pollutants, or at the very least, control their emissions. This is also the most cost effective approach, as the alternative, increasing the ventilation rate, will raise energy costs. Make a list of the contaminants mentioned plus any others that you are aware of and make copies. Make certain that when you meet with a Custom Vac or an independent consultant to discuss your particular situation that you provide a copy of your findings.

In some cases, controlling the pollutants will not be enough and some form of mechanical ventilation necessary. Infiltration, the process of outdoor airflow into a building through cracks in walls, floors or ceilings, or through joints and around windows, is almost non-existent with modern construction. So, it is not enough to just open a door or window - it is impossible in many modern buildings. Also, conditions have to be just right for this method to work.

Good Air Exchange Rate Needed

The answer in most cases will be mechanical ventilation. The goal in any building is to have a good air exchange rate. The needs of each home or building will vary. The answer for a home may be as simple as installing outdoor-vented fans in the two rooms that typically give off the majority of pollutants: the kitchen and bathroom. In the case of larger homes or buildings, an effectively operating air handling system will be the solution. Use the following points to ensure the air handling system is working at full capacity:

  • check the outdoor intakes for dirt, debris and blockage

  • be sure the controls are functioning properly, and all set points correct

  • after ensuring the controls are operating correctly and

  • check that exhaust fans are operating to full capacity

If a problem still exists after following these steps, the problem could be in the design of the ventilation system.

As mentioned earlier, Custom Vac will play a key role in assisting you to improve the IAQ in your home or building. Custom Vac Limited continues to upgrade and train its technicians regarding ventilation systems. Custom Vac Limited prides itself in being able to educate the homeowner or building owner as to practical solutions to improve IAQ. For example, the introduction of integrated (combo) systems such as the Lifebreath Clean Air furnace is making heating and ventilation more affordable.

Some of the information contained herein was taken from the May 1998 HRAI Technical Link "Taking control of IAQ." HRAI is an Industry Trade Association that we are proud to be a member of. HRAI provides the certified training programs that our technicians complete. If you are looking to hire a heating, ventilation, air conditioning and refrigeration (HVACR) contractor, ask if they are a member of HRAI and if they have HRAI Residential Mechanical Ventilation certified installers. If not, look for one that does.

Mechanical Ventilation Equipment - HRV/ERV?? Confused??

For the freshest, healthiest indoor environment, you need to take a serious look at mechanical ventilation. Typically in buildings, stale air is recirculated with no fresh air except when a window or a door is opened. In some buildings there might be a fresh air duct piped into the return air of the furnace. This is known as passive ventilation because it relies on the building to be leaky, fresh air is drawn in through a duct, heated and distributed. This method is no longer acceptable as furnace manufacturers are demanding a minimum of 60F return air temperature. Considering rising energy costs, retrofitting our homes with better windows, doors, insulation, etc., while relying on passive ventilation no longer meets even the minimum requirements of today's ventilation standards.

The air in your home or office may be too dry or too humid, or laden with a host of indoor air pollutants including harmful living airborne organisms. There is no one solution. Custom Vac provides its customers with a thorough evaluation of problem areas and a set of alternatives to enhance your air quality. Sometimes health problems of the occupants are so severe yet there are no visual signs apparent. In these homes we work very closely with a consulting company who can assist us with the evaluation and recommendations.

Solving the Problem

Solving indoor air quality problems requires a good understanding of the "house as a system" (for every action there is an opposite reaction). A concept that basically tells us that when we change one thing, such as add new windows and doors to reduce energy consumption, there may be an increase of indoor humidity as a result of less air leaking from the building. Your home or office needs to be attended to by professionals. Why trust anyone other than Custom Vac? They have the knowledge and expertise to solve your indoor air quality problems.

Residential and commercial Energy Recovery Ventilators (ERV) and Heat Recovery Ventilators (HRV) are designed to provide you with the best indoor environment possible. Both these units exhaust stale air and introduce fresh air back into the home. The difference is in the heat transfer cores. An HRV is used in applications where very high humidity applications exist and will continue even when a proper ventilation rate has been determined. They only recover sensible heat and require a defrost time.

An ERV, on the other hand, is used in applications where not all the moisture is exhausted. Both sensible heat energy and latent heat energy (water vapour) is recovered. In the winter, the ERV can recover up to 30% more energy and in the summer can reject more than 3 times the amount of unwanted outside heat and moisture.

Enthalpic (ERV) heat and humidity transfer cores require no condensate drain, no defrost cycle and can be mounted in any position. This technology efficiently transfers both heat (sensible energy) and water vapour (latent energy), while excluding pollutants. Cores are made of a special proprietary resin-composite medium that has demonstrated no loss of operating efficiency over the long term, while retaining strong resistance to the transfer of pollutants and biological contamination.

ERVs have been used successfully in installations for over a decade. As global markets continue to open up, we will have access to many more new and innovative products. HRVs and ERVs today have proven reliable and make a significant improvement to improving the indoor environment in any home or office.

Custom Vac - Heating - Cooling - Air Quality Control - Duct Cleaning - Systems Analysis,  Winnipeg, Manitoba. Since 1970.Home Comfort Center   Home Comfort Center
Custom Vac - Heating - Cooling - Air Quality Control - Duct Cleaning - Systems Analysis,  Winnipeg, Manitoba. Since 1970.Honeywell   Honeywell
Custom Vac - Heating - Cooling - Air Quality Control - Duct Cleaning - Systems Analysis,  Winnipeg, Manitoba. Since 1970.Venmar   Venmar


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Custom VAC Ltd.
1567 Logan Avenue
Winnipeg, Manitoba
R3E 1S5
T. 204-775-7744
T. 204-772-5799
F. 204-774-8557


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