How to Select The Right HVAC Unit
Consider These Factors When Selecting Your New Air Conditioning Unit
Size A synonym for the air conditioner’s cooling capacity, size is measured in British thermal units per hour (Btu/hr.) or in “tons.” One ton of cooling equals 12,000 Btu/hr.
There are several factors that determine what will be the best size of air conditioning system for your home: square footage, ceiling height, number of windows, and insulation. The correct sizing of your unit does matter.
- An air conditioner that is too small will not be able to keep up with load requirements on a really hot day.
- An AC system that is too large will cycle off and on too frequently and do a poor job of dehumidifying the air, which degrades comfort.
- It is better to slightly undersize an air conditioner than to oversize it.
These factors, as well as how well your home is insulated, how it’s used by you and your family, the climate in our area, and more must be taken into consideration when selecting and designing your system. For the purpose of estimating you will need:
- 1 ton of capacity for every 600 square feet of living space in a marginally insulated house located in a hot-in-summer region (2,000-square-foot would probably need a 3.5-ton air-conditioning system).
Efficiency This describes how much cooling the unit delivers for each watt of electricity. Efficiency is expressed as the seasonal energy-efficiency rating, or SEER. The minimum SEER for a split system central air conditioner allowed today is 14, so look for units with SEER ratings of 15 or greater. The higher the SEER, the more you can lower your energy costs.
A question we commonly hear is that a 16 SEER air conditioning unit is more expensive than a 14 SEER unit and is it worth it? Though only you can make that decision, some factors to consider are:
- 16 SEER unit uses about 13 percent less energy than a 14 SEER unit (If you spend $100 in energy costs with a 14 SEER unit, you would only spend about $87 with a 16 SEER unit)
- 16 SEER energy users is that the units have a two-stage compressor.
- Unit adapts to conditions within your home rather than having to run at full speed or shut off.
- Unit can run quieter and for more extended periods of time, reducing the humidity in your home over time (usually one of the main sources of discomfort.
Upgrading an existing system If you’re upgrading your central air, don’t assume you should buy the same-sized system. Any changes you’ve made to improve your home’s energy efficiency, such as upgrading your windows or adding insulation, can reduce your cooling needs. On the other hand, if you’ve added rooms, you might need more cooling.
Our team can do a load calculation based on a recognized method, such as one in Manual J from the ACCA. Our evaluation will include whether your ducts need to be resized, sealed and insulated, or replaced. Remember that an indoor evaporator coil and outdoor condenser must be a matched set from the same brand, or the performance, efficiency, and capacity might not meet expectations.
New systems are 20 to 40 percent more efficient than minimum-efficiency models made even 10 years ago. Costs will vary and can depend on whether you need ductwork installed, and the particular size and configuration of your home.