5 things to look for in a new HVAC system
The early record high temperatures have many businesses worried about the cost of keeping cool for the rest of the summer. If you have an older HVAC (heating, ventilation and air conditioning) system, this might be a good time to consider a more efficient replacement. Not only will your investment be offset by reduced monthly energy bills, you may be able to trim costs further through available rebates and incentives.
A new HVAC system is a huge investment, so spend time shopping and comparing before replacing old equipment with the same type and size of equipment. With all the new developments in HVAC technology, it’s very likely you will be able to achieve greater comfort and performance with a smaller unit.
Here are five things you’ll need to consider.
- BTUs. You will hear a lot of references to BTUs, which is shorthand for British thermal units. Basically, BTUs represent the level of heating or cooling output for an air conditioner, furnace or boiler.
- Tons. Equipment size is defined in “tons,” but that does not mean how much it weighs. Each ton represents 12,000 BTUs of energy output. Generally, one ton is needed for conditioning every 400-500 square feet of floor space. A traditional 5,000 square foot building would require a 10-ton unit. More efficient buildings may only require one ton of output for every 650-1000 square feet.
- SEER rating. The efficiency of an AC unit is defined by its Seasonal Energy Efficiency Ratio (SEER), how many watts it takes to deliver the BTUs needed during a particular cooling season. The higher the SEER rating, the less energy the AC will need to cool the space.
Many older ACs have SEER ratings of six or less. The minimum SEER allowed today is 13, but consider purchasing equipment with higher SEER ratings for bigger savings. Missouri utility companies offer rebates ranging from $10- $188 per ton for high efficiency air conditioning units.
- AFUE ratings for furnaces and boilers. The efficiency of furnaces and boilers is defined by their Annual Fuel Utilization Efficiency (AFUE), which shows how much of the used fuel is actually converted to heat.
For example, if a business switches out a 60 percent AFUE furnace for an 80 percent AFUE unit, the new furnace would use 60/80 or 3/4 the amount of energy to produce the same amount of heat. This could cut one quarter of the cost of monthly heating bills during the winter.
Old, low-efficiency heating systems generally have an AFUE between 68 and 72 percent, whereas a medium-efficiency system is generally 80-83 percent AFUE. Although high efficiency units (rated between 90-97 percent AFUE) require a higher upfront investment, these systems will save the most money in the long run. Missouri utilities offer rebates between $150 to $475 for high-efficiency gas furnaces, and up to $3,000 in rebates for high-efficiency commercial boilers.
- Dual fuel. A combination gas furnace and air source heat pump is more economical than a gas furnace alone. An air source heat pump uses air temperatures to pre-warm or pre-cool the air, using less energy to reach the desired temperatures. In many cases the gas furnace is used as a backup, although in warmer climates a gas furnace may not be needed at all. A heat pump can deliver one-and-a-half to three times more “heat energy” than the electrical energy it consumes.
Heating efficiency for air source heat pumps is indicated by the heating season performance factor (HSPF), which is the number of BTUs divided by the total watts needed for a particular heating season. Again, this is just a way of saying the amount of energy it takes to keep the building warm. The most efficient heat pumps have an HSPF between 8 and 10.
Cooling efficiency for heat pumps is defined by SEER. The most efficient units have SEER ratings between 14 and 18. Missouri utilities offer rebates from $40 to $188 per ton for air source heat pumps.
For more information on utility rebates, visit the Environmental Assistance Center’s Efficiency and renewables section.
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