Maintain it, Fix it or Freeze!
The furnace that warms your house is likely to be the most expensive home appliance you will purchase and operate. There is also the installation cost that may be as much as the unit itself, whether it is for heating only, or part of a combination unit for heating and air conditioning. Your furnace is a combustion appliance, meaning it burns fuel to create heat. This in turn means that proper selection, installation, inspection and maintenance of your appliances are extremely important in reducing your exposure to combustion pollutants. Providing good ventilation in your home and correctly using your appliance can also reduce your exposure to these pollutants. Never ignore the smell of fuel This usually indicates that the appliance is not operating properly or is leaking fuel. Leaking fuel will not always be detectible by smell. If you suspect that you have a fuel leak have it fixed as soon as possible. There may be a slight smell when you start up your furnace at the start of the cold season. If it does not last long, it is probably just dust and dirt burning off.
There is no question that newer furnaces are more efficient, most have an AFUE (Annual Fuel Utilization Efficiency) of at least 78%. Older furnaces that use pilot lights may be in the 50-55% range.
Another factor is the life expectancy of a heating system. The typical life is about 25 years much longer for some boiler systems. You will also want to get the right size of unit. If your home has been updated with new insulation and energy saving windows you might not need as large a unit.
A Word About Installation – Get An HVAC Contractor
It goes without saying that you should choose an experienced and reputable installer who will make sure all the extra components of a heating system are working efficiently and that they fit with your choice of furnace. This includes such things as the thermostat and ductwork. You should have your HVAC (Heating, Ventilation and Air-Conditioning) contractor perform a heat loss analysis to determine the right size equipment. Ask your furnace supplier and/or HVAC contractor to explain the terms Single Stage, Two Stage and Variable Speed. Here is a simplified explanation. A single stage furnace gives the same heat and airflow at all times no matter what the temperature outside. A two-stage furnace starts at a lower burning and lower airflow stage and only goes to the higher burning and higher airflow stage if the temperature drops further. A variable speed fan motor provides better circulation and temperature distribution, cleaner air due to the air being filtered more, greater efficiency, and a quieter operation.
Maintenance and Inspection
The best advice is to follow the recommendations of the manufacturer. The same combustion appliance may have different inspection and maintenance requirements, depending upon where you live.
In general, check the flame in the furnace combustion chamber at the beginning of the heating season. Natural gas furnaces should have a blue flame with perhaps only a slight yellow tip. Call your appliance service representative to adjust the burner if there is a lot of yellow in the flame. LP (liquefied petroleum) units should have a flame with a bright blue center that may have a light yellow tip.
On a regular basis have flues and chimneys cleaned and inspected for leakage and for blockage by creosote or debris. Creosote buildup or leakage could cause black stains on the outside of the chimney or flue. These stains can mean that pollutants are leaking into the house. Have the combustion chamber cleaned, adjust burners, and check the general operation.
Does Your Furnace Need an Annual Check-Up?
Check the warrantee. This might be the deciding factor for you. Some sources say the furnace should be checked on an annual basis, others say every 3 years is sufficient.
There are several reasons for this. Most furnaces and air conditioners are built to run with very little maintenance. If you regularly clean or install new return-air duct filters, that is all you typically need to do to make sure your furnace operates well. The only people who must do annual work are those with oil furnaces. It is a great idea to install a new in-line oil fuel filter and a new atomizer nozzle to get maximum efficiency. Natural gas or propane furnaces need very little service.
Check your chimney for blockages; make sure the flue pipes are in great shape. Simply look over your equipment and see what it looks like.
Ground Source Heat Pump vs. Propane Furnace
Water-to-water heat pumps are used with geothermal heat sinks/sources — otherwise known as ground source heat pumps. The trouble with geothermal is the high capital cost of the equipment and the installation, including the underground tubing. If you have an underground water source (i.e. two wells) the underground portion of the heating system will be less expensive (shorter) than if it is ground coupled. Both types will be more expensive than conventional heating, but will be able to give you air-conditioning. The key of course is that with such a constant heat source (temperatures don’t change much summer to winter deep in the ground), the machine becomes very efficient and very inexpensive to operate.
You need a large lot for the installation (you are in the country) and a large heat demand (you do have 3300 sq.ft.) to justify needing to generate a lot of low cost heat. Payback periods start to become attractive (say 5 or 6 years) with houses of 4000 or 5000 square feet. If you are willing to wait a little longer it may be worth your while, especially if you believe that fossil fuel prices really are going to double this winter.
If you do go with the ground coupled heat pump make sure you find an experienced contractor with good references. This can make all the difference between a system that works efficiently with minimal expenditure, and an expensive system that gives you problems.
General Potential Problems for Gas or Oil Furnaces
Cracked heat exchanger;
Not enough air to burn fuel properly(See Below);
For all of these problems you will need to hire a professional furnace service to see to correction and repairs.
Trouble Shooting: Does My Furnace Get Enough Air?
A combustion furnace or boiler (gas, oil, coal or wood) requires air to burn and air to maintain a proper draft in the chimney. In a leaky old house with the furnace in an open basement this is never a problem. As houses become better sealed, several problems can arise:
An automatic ventilation system will supply ample air to the house but, if it fails or freezes up, the furnace could become starved for enough oxygen to burn cleanly or to maintain a proper draft.
Every exhaust fan in the house is competing with the furnace for air, which could cause dangerous polluting chimney back drafts. In fact, the building code requires special provision for combustion make-up air whenever you have exhaust fans that are larger than 75 liters/sec (150 cfm). Manufacturers of powerful indoor bar-b-que range top exhaust fans (often 300 to 600 cfm) do not acknowledge that installation of their fans without some significant work to provide failsafe air to the furnace when they are operating is in violation of the building code, and downright dangerous for the occupants of the house.
A hot fire in a fireplace that does not have its own fresh air supply will almost always outdraw a furnace if the two must compete for the same available air.
Here are two simple tests to evaluate if your furnace has a sufficient air supply:
First, test if you ‘might’ have a problem. Close all the doors and windows in the house, as well as the fireplace damper and the cold-air intakes on any ventilating system. With the furnace off, watch the smoke from or incense held near the barometric damper in the flue pipe of an oil furnace; below and near the back draft hood above a gas furnace; or in front of the intake vents of a solid fuel furnace — the smoke should go up the chimney.
Now, have someone turn on all the exhaust fans in the house at the same time, including the clothes dryer if it exhausts outside. Continue observing the furnace for at least 15 minutes to allow the fans to exhaust the house. If the smoke noticeably stops going up the chimney and particularly if it obviously turns around and flows into the house, you should consider adding a combustion fresh air supply.
Now, open the fireplace damper and light your fireplace. If the incense smoke turns around (which it most probably will do, whether or not it did before) you do need a fresh air supply especially for your fireplace, whether or not you install one for the furnace.
Second, do the same things with the furnace operating If the exhaust fans or fireplace can turn around the incense smoke while the chimney is full of hot gas — you definitely need a combustion fresh air supply.
These tests are not foolproof, but they include a margin for error on the safe side. It can certainly indicate whether it is worth the trouble to professionally pressure test the house and/or consult a furnace expert.
The codes are constantly changing as we recognize the problems of competition for air in modern houses. Where the code requires combustion air for your furnace or boiler, don’t sidestep the issue, even in renovation where codes are not as thoroughly enforced as in new construction.
This paper is intended for informational purposes only. Nothing contained herein constitutes legal, financial or other professional advice. Transmission of these materials is not intended to create, and receipt does not constitute, any relationship of any kind between the provider and the recipient. Some of these points may not apply in your area. Different term and conditions may vary from state to state and province to province. All articles, text and photographic material presented here is for the use and pleasure of the recipient only. Download PDF