Here are some Frequently Asked Questions related to HVAC, Heating, Ventilation, and Air Conditioning.

In most cases a service call will be needed to fix these problems, but some of them can be fixed without having to call for the help of a technician. If you are experiencing a problem requiring attention, and if you are in our service area you can call us at (925) 447-1500 or click here to email our service department.

Heating and Cooling Efficiency Ratings Explained
As you search for the ideal HVAC system, you will encounter various industry-standard efficiency ratings. The higher efficiency your system, the lower your long-term energy usage and the greater your savings will be. In addition to offering high-quality products and exceptional customer service, we want to provide information so you can make informed, educated decisions about your heating and cooling system.

There are three main ratings to pay attention to when selecting a heating or cooling system:

  1. SEER (Seasonal Energy Efficiency Ratio) measures and rates the efficiency of the cooling processes in air conditioners and heat pumps. All new products are required by law to have a minimum 13.0 SEER rating.
  2. AFUE (Annual Fuel Utilization Efficiency) measures the efficiency for gas and oil-fired furnaces. This rating uses a percentage to tell how much fuel is used to heat your home versus how much fuel is wasted.
  3. Cost Savings: If you replace a furnace with an AFUE of 60% with a new, highly efficient furnace, you could save up to 40% on your heating bills. You can easily and quickly recover the cost of replacing your old furnace through lower utility bills.
  4. HSPF (Heating Seasonal Performance Factor) measures the efficiency of a heat pump’s heating mode. All new models are required to have a minimum 6.8 HSPF rating.

Cost Savings: Although higher efficiency heat pumps and air conditioners typically have higher equipment costs, they do lead to lower utility bills. In a warm and/or humid climate, a building owner can usually recoup the costs of buying high efficiency equipment through lower utility bills in a short few years.

Why is my furnace blowing out cold air?
It could be a thermostat problem, something is in the flue, transformer, or with the “Main Board”.

My furnace has a funny smell, what could it be?
It could be dust, animal hair, and/or burning pollutants. These causes are harmless but can cause an unpleasant odor. More seriously, it could be a gas leak.

How can I tell whether my furnace has a CARBON MONOXIDE leak?
Have your power company or Select Mechanical check for cracks in the heat exchanger.

Why does my furnace not put out enough heat?
It could be improper design of the original system or improper combustion, restricted air-flow, leaks in the duct work. All could play a role.

Why is my furnace so noisy?
It could be a worn belt, bad bearings, or bearings in need of lubrication.

Why do the registers at the far end of my office have little or no air flow?
The duct work could be leaking or the TRUNK LINE (improper design) could be the wrong size.

My allergies seem to bother me a lot when the system is operating. What can I do?
First, change your AIR FILTERS. You might also consider having you AIR DUCTS cleaned. Much of the dust, mites and other debris that build up in the AIR DUCTS are circulated into the air of your work place.

What are the benefits of an AIR FILTRATION system?
An Air filtration system removes dust, pollen, spores, and smoke. It can also reduce the cost of Furnace and Air Conditioner maintenance.

How do I choose a humidifier?
It is very possible that more than one model humidifier may work for your work place, and your contractor can help you choose the best for your application. The most qualified person to help you decide which humidifier will best fit your needs is your local HVAC contractor. Select Mechanical can recommend and install the best unit for your work place based on its size, age and construction.


For additional information or to arrange a consultation, please contact us at 925-447-1500 or