FAQ on HVAC

  1. Why is my system not heating / cooling?
  2. How do I know what kind of heat & air conditioning system I have?
  3. Doesn’t a gas furnace cost less to run than a heat pump?
  4. Doesn’t a gas furnace supply more heat than a heat pump?
  5. I still want a gas furnace, what kind should I get?
  6. You seemed prejudicial towards heat pumps, don’t they blow cold air?
  7. Is it better to have two systems/zones?

1. Why is my system not heating / cooling?

When your equipment doesn’t seem to be working, first check these 5 items.

  • Is the filter clean?
  • Is the thermostat set properly? (Some digital T-stats have a 5 minute time delay)
  • Is the indoor furnace/air handler switch turned off?
  • Are any of your electrical panel breakers tripped?
  • Is the indoor fan, outdoor fan, & compressor running?

If you don’t find any problems and your equipment still is not functioning properly call the office at 540.659.3118 for a service technician to come to your home.

2. How do I know what kind of heat & air conditioning system I have?

A heat pump is an all electric system. Therefore, if you have a central forced air heating system (that means a central fan & ductwork) but don’t have a gas or LP bill you probably have a heat pump. If you see a metal flue pip or a 2″ or 3″ white PVC flue pipe coming out of the equipment in your basement it is probably a fossil fuel furnace of some kind. A separate coil on top of the furnace box is another clue that you have an air conditioner & gas furnace combination.

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3. Doesn’t a gas furnace cost less to run than a heat pump?

In general, the answer to this question is no, especially if you live in Virginia. With the deregulation of the utility companies, fossil fuel prices have been increasing while electricity has remained comparatively stable. In addition, the Federal government has convinced many industrial and commercial enterprises to change over to ‘clean burning’ natural gas via tax incentives. The resulting demand for natural gas is beginning to outstrip supply and exceed the capacity of the existing gas delivery infrastructure. To cope, the industry will have to continue to raise prices on fossil fuels. This all goes double for Liquid Propane. LP never makes sense financially.

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4. Doesn’t a gas furnace supply more heat than a heat pump?

A fossil fuel product should have a higher supply air temperature than a heat pump but will traditionally supply a smaller volume of heated air than a heat pump for a given dollar value of fuel. The best analogy is that if you are sitting in a tub of 70 degree water and I offer you a choice between 1 gallon of 130 degree water or 4 gallons of 90 degree water. Which do you think will warm you up the most? Obviously there is much more heat energy in the 4 gallons of 90 degree water than the 1 gallon of 130 degree water.

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5. I still want a gas furnace, what kind should I get?

We at Stafford Heating and Air understand that some people want a fossil fuel heating system and are willing to pay the difference in fuel costs. If that is the case, we strongly recommend you purchase a 95+ AFUE furnace. ESPECIALLY if you are going to burn Liquid Propane. Liquid Propane is the most expensive way to heat a home in Virginia and only should be considered in places where there is insufficient ampacity for a heat pump system. A Trane XV95 or XC95m is the finest furnace manufactured and is a good place to start looking. Consider the extra cost of an efficient furnace as an investment in the future. As fossil fuel prices continue to rise, the extra efficiency you buy now will pay greater and greater dividends in the future..

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6. You seem prejudicial towards heat pumps, don’t they blow cold air?

The “blow cold air” phenomenon has been associated with heat pumps ever since they were first released. A modern heat pump should supply air at least 20 degrees above the room temperature when the system is running at 100%. A variable speed air handler will make sure the air is hot before it comes out of the supply registers by starting up slowly instead of coming on all at once. The blow cold air effect usually comes from the supply registers blowing directly on the occupants of a room. When this happens, the effect is similar to sitting under a fan in the summer. The increased airflow over the room occupant increases his or her heat loss through evaporative cooling so that they feel chilled. This is one of the reasons that a proper duct work layout should not blow supply air onto any occupant if at all possible. If you feel a lot of air movement out of some supply registers, chances are there isn’t any air flow out of other supply registers. A variable speed air handler or furnace can help alleviate this problem through longer run times but nothing can replace a good duct system. There was a reason the heating contractor your builder chose was the lowest bid.

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7. Is it better to have two systems/zone… ?

Have two separate systems in a house only makes sense when the total cooling load of the house exceeds the capacity of 5 tons or so. Five ton systems are the largest commonly available residential equipment size and so larger loads will need more than one system. Otherwise, all you are getting with two systems is twice the repair bills. My favorite example is comparing the situation to cars. Two cars cost more to buy and maintain than one don’t they? Same goes for your air conditioning.

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