Ace Air, Inc. Blog: Posts Tagged ‘Ventilation’

Heating Guidelines: Heating System Ventilation 101

Friday, January 20th, 2012

 

Maintaining Proper Ventilation for Combustion Systems

Anytime you maintain, retrofit, or replace a gas heating system in your Turlock home you also need to be concerned with air quality. Combustion air is needed by all oil and gas heating systems to support the combustion process. This air is provided in some homes by unintentional air leaks, or by air ducts that connect to the outdoors. The combustion process creates several byproducts that are potentially hazardous to human health and can cause deterioration in your home. You can protect yourself from these hazards, as well as maintain energy efficiency, by ensuring that your chimney system functions properly and that your gas heating system is properly ventilated. In some cases, installing a sealed-combustion furnace can also help.

Chimneys

Properly functioning chimney systems will carry combustion byproducts out of the home. Therefore, chimney problems put you at risk of having these byproducts, such as carbon monoxide, spill into your home.

Most older gas furnaces have naturally drafting chimneys. The combustion gases exit the home through the chimney using only their buoyancy combined with the chimney’s height. Naturally drafting chimneys often have problems exhausting the combustion gases because of chimney blockage, wind or pressures inside the home that overcome the buoyancy of the gases.

Atmospheric, open-combustion furnaces, as well as fan-assisted furnaces, should be vented into masonry chimneys, metal double-wall chimneys, or another type of manufactured chimney. Masonry chimneys should have a fireclay, masonry liner or a retrofitted metal flue liner.

Many older chimneys have deteriorated liners or no liners at all and must be relined during furnace replacement. A chimney should be relined when any of the following changes are made to the combustion heating system:

When you replace an older furnace with a newer one that has an AFUE of 80% or more. These mid-efficiency appliances have a greater risk of depositing acidic condensation droplets in chimneys, and the chimneys must be prepared to handle this corrosive threat. The new chimney liner should be sized to accommodate both the new heating appliance and the combustion water heater by the installer.

When you replace an older furnace with a new 90+ AFUE appliance or a heat pump. In this case, the heating appliance will no longer vent into the old chimney, and the combustion water heater will now vent through an oversized chimney. This oversized chimney can lead to condensation and inadequate draft. The new chimney liner should be sized for the water heater alone, or the water heater in some cases can be vented directly through the wall.

Other Ventilation Concerns

Some fan-assisted, non-condensing furnaces, installed between 1987 and 1993, may be vented horizontally through high-temperature plastic vent pipe (not PVC pipe, which is safely used in condensing furnaces). This type of venting has been recalled and should be replaced by stainless steel vent pipe. If horizontal venting was used, an additional draft-inducing fan may be needed near the vent outlet to create adequate draft. Floor furnaces may have special venting problems because their vent connector exits the furnace close to the floor and may travel 10 to 30 feet before reaching a chimney. Check to see if this type of venting or the floor furnace itself needs replacement. If you smell gases, you have a venting problem that could affect your health. Contact your local utility or Turlock heating contractor to have this venting problem repaired immediately.

Chimneys can be expensive to repair, and may help justify installing new heating equipment that won’t use the existing chimney.

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How Much Ventilation Do I Need for My Cressey House?

Friday, January 13th, 2012

By now you’ve probably heard how important it is to have good ventilation in your Cressey home. Especially if your home was built in the 1980s or early 1990s when ventilation issues were prevalent, you may not have enough clean air moving through your home. But, how much ventilation do you need? What is enough and if you don’t have it, how do you ensure your home is retrofitted properly?

How Much Ventilation?

Most recommendations for ventilation come from the Home Ventilation Institute, which provides a series of standards of measurement for builders and contractors retrofitting homes for better ventilation. Here are some of their recommendations and how they might apply for your home:

  • Bathroom – Small bathrooms (less than 100 sq. ft) need 1 CFM per square foot of bathroom. The number goes up for each fixture if you have a large bathroom.
  • Kitchens – Your kitchen range needs at least 100 CFM if against the wall and upwards of 150 CFM if on an island.
  • Ventilators – If you have an HRV for your home, you should have at least 100 CFM for 2,000 square feet and another 50 for every 1,000 square feet of home size being ventilated.
  • Home Ventilators – The actual volume of CFM for ventilators depends on the type of ventilator being used. For example, a whole house ventilator needs upwards of 6,000 CFM for a 2,000 square foot home. Attic ventilators need 1,400 or more.

So, what does this mean for your Cressey home? It means in general that you need a lot of ventilation and that the best way to get it is through mechanical ventilation techniques combined with your air handler and ductwork.

Especially if you recently added insulation and weather proofing to your home but have not yet updated your ventilation, you might have a major air quality problem, so have a Cressey professional measure your home’s air flow as soon as possible.

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