High-efficiency Heating and Cooling Systems

If  you're building a new home, or renovating, you'll be looking into options for heating and cooling. But with the wide array of options, which do you choose?

Some of the common high efficiency options include condensing gas and oil furnaces, heat pumps and ground source heat pumps (GSHP or geothermal) systems. But which is "best?"

All of these can be good options depending on your home's design, currently installed systems, budget and fuel availability. In this article, we'll briefly summarize the options and provide some pointers to help you select the best option for your specific situation.

Currently, the federal government has some generous tax incentives for high efficiency heating systems. If you install a GSHP or solar hot water system, you can get a 30% tax credit with no cap. This is extremely generous and shifts the economics of these systems considerably.


In addition, there is a 30% tax credit of up to a total $1500 for other energy efficiency improvements. This is for all efficiency improvements and may include heating/cooling systems, windows, insulation, etc. This is separate from the renewable tax credit.

With the current incentives, GSHP is much more cost effective than in the past. With a typical installation cost of $25,000-$30,000, GSHP systems were historically out of the price range of many consumers. However, with the incentive, that comes down to a range that is more in line with other high efficiency options.

If you are building a new home, there is no other option that offers all the efficiency or cost effectiveness of a GSHP. With rising utility costs, the specific savings vary, but in general, the numbers strongly favor this type of system for new construction.

For existing homes, things get more complicated. Some homes have radiators or baseboard hot water heating, others have forced air furnaces. Some homes are large, others are small. Some are well insulated, others are cold and drafty. With so many differences, it makes choosing a system quite difficult. However, it does narrow down the options.

Remember, the most efficiently used energy is the energy that isn't used at all. Building a tight, highly insulated home is the most important step you can take to reducing your energy bills. Plus, the more energy efficient the home, the smaller and less expensive the heating system that is required. It is always best to insulate and air seal a home before installing a new heating/cooling system.

If you currently have a hot water system with radiators or baseboard heaters, a GSHP may not be suitable for your home. If you have central air, then you may be able to retrofit it with a GSHP and continue using your existing hot water system as a backup or to even out the temperature. However, if you do not, it can be very difficult/expensive to add ductwork, especially in an old Bucks County farm house. In this situation, GSHP systems do not work well because they cannot supply hot enough water for radiators or baseboards.

In situations where you must or want to keep using hot water heating, then it pays to get a high efficiency boiler. Currently, condensing gas systems are the most reliable high efficiency systems on the market. With efficiencies of up to 95%, these systems squeeze almost every BTU of heat out of the fuel. Additionally, natural gas is currently the least expensive fuel on a cost per BTU basis. Importantly, propane, while similar to gas, is one of the most expensive ways to heat your home. You have to be very careful when choosing systems that you don't get locked into an expensive fuel.

There are also 95% efficient oil systems available, however these systems are very finicky and prone to malfunction. Fuel oil in the United States is lower quality than these systems were designed for, so they tend to clogs and break down. For this reason, super efficient oil systems are not recommended.

However, there are some very good conventional high efficiency oil burning systems, typically rated at about 85% to 88%. Some, such as the Energy Kinetics System 2000, have special electronics that allow them to run much more efficiently than other units with similar efficiency ratings. If you're locked into oil and hot water distribution, these systems can work very well.

If you're planning on replacing your air conditioner, you might consider replacing it with a high efficiency heat pump. While heat pumps have a bad reputation for blowing cold air, modern units are much better than in the past. The key thing is to size it for the heating requirements of your home. Usually, they are sized for the cooling, but in our climate, this leads to unsatisfactory heating. With a modern, two stage heat pump, you can size it for the heating needs without compromising the cooling capacity. In our climate, a two stage heat pump works much better than the lower efficiency single stage unit and is well worth the added cost.

A final option to consider is the ductless mini-split heat pump. These systems have outdoor condensors, just like your central air system, but instead of installing ductwork throughout your home, you place a compact unit on the wall. These systems work extremely well for additions or areas that are poorly serviced by an existing system, such as master bedroom suites. There are a wide range of these on the market, but only the "inverter" style systems are high efficiency. One of these, the Fujitsu RLS series is actually as efficient as most GSHP units! I have installed two of these in my own home and have reduced my summer cooling bills substantially.

As you can see, there are many options for efficient heating and cooling, depending on your home and your budget. There is no single "best" system for all homes. A qualified heating consultant can help you choose the best system for your specific needs.

References:

Database of Incentives for Renewables and Efficiency (DSIRE)

DSIRE Residential Renewable Energy Tax Credit

DSIRE Residential Energy Efficiency Tax Credit

International Ground Source Heat Pump Association

Properly Sizing a Heat Pump

This article was written by Ted Inoue of Energy Testing & Consulting LLC.


Ted Inoue
Energy Testing & Consulting llc.
New Hope, PA 18938
215-760-0211
http://www.etccreations.com/


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