Wednesday, February 27, 2013

Deflate Your Heating Bills with a Heat Pump While Putting a Stopper in More Fracked Gas and Oil Pipelines


In the last blog you learned how to “Tear up Your Energy Bills” with solar photovoltaic. And we promised to talk next about heat pumps. Heat pumps can heat your new home and replace your aging oil or gas furnace, whether in a rural or suburban setting or in the city. Unlike solar, you can install them in the shade and keep your trees, and like solar, there are a lot of tax credits and incentives - and the price is coming down. The other dividend is that you heat your home – not your planet.
Okay, just what is a heat pump? How does it work? Well, there are several kinds but lets talk about a ground source, or ground loop, reversible heat pump. A large loop of pipe is installed underground, often in the water table, where the ambient temperature is always about 50⁰F at Massachusetts’s latitude. That loop of pipe carries a fluid that cools in the summer or heats in the winter. Highly efficient, reliable and quiet pumps and heat exchangers circulate that fluid through that loop of pipe to heat up the cold winter air to heat your house (like a refrigerator operating in reverse) and to cool the hot summer air to air condition it. It just needs enough electricity to power the pumps.

By the way, it is not new, untried science. It is an old technology with modern materials. It has few moving parts and requires little maintenance.

What does it take to heat your house? This is measured in millions of BTUs, which are British Thermal Units. A 1,500 square foot house in Boston, Massachusetts would about 63 mBTUs per year. The comparative operating cost of oil, natural gas and a heat pump has been estimated by others, here for example, and the reversible ground source heat pump comes out ahead.

What about the cost to buy and install it? Ideally, if you are building a new house or buying one from a subdivision to be developed, it is a lot cheaper to put in the heat pump then. So yes, retrofitting an existing house is more expensive up front but it is economic over its lifetime. A room by room retrofit with an air source heat pump, discussed below, may be better. But an awful lot of oil and gas fired furnaces in the state are old and inefficient and need replacement, and, unlike heat pumps, produce CO2 and other green house gases as well as some toxins. Nor does a new fossil fueled Energy Star oil or gas furnace get you the state and federal tax credits. But Energy Star rated heat pumps system do qualify for those Energy Star rebates too. Moreover, Massachusetts needs as robust a thermal renewable energy credit market for residential heat pumps  as it has for solar RECS as a further incentive to convert to clean energy heat pumps.

What about your pocket book? As there are for solar pv or thermal on your roof, there is federal tax credits for ground loop heat pumps of 30% of equipment, installation and labor costs. There is no dollar restriction on the tax credit. The heat pump must be installed in an owner-occupied home and meet certain requirements. A list of qualified ground source heat pumps is provided by energy star. Under current law, this tax credit lasts until 2016, but like most such renewable energy credits have been, they  will probably be renewed too.
Is there a heat pump alternative to a ground loop? You bet there is. It is called an Air-Source heat pump. That can receive a federal tax credit up to $300 for heating if it is installed in a family’s principal residence and $500 for cooling. It is usually installed one per room, uses electricity and is very quiet. It is more expensive to have one that both heats and cools. You can find listings of qualified air source heat pumps at energystar.com.
Are there loans available to help pay for it? The Massachusetts Heat loan program allows participants to receive a 0% interest loan to finance qualified energy improvement installations related to the home, and heat pumps can qualify. These loans are available up to $25,000 on a 7-year term. To qualify, your home must have a Mass Save Home Energy assessment and meet certain energy efficiency standards. More information on the Mass Save Heat program can be found at masssave.com.
 How do I pick an installer? The Massachusetts Sierra Club has an alliance with Energy Sage that will help you find one and assess different options. Just link here to Energy Sage to start that process. Energy Sage will help you shop around to get the best prices and financing terms as well as a reliable installer.
These are some of the basics. And there are types of heat pumps other than the ground loop and the air source heat pump discussed above. They have various names, such as ductless mini-split, geothermal, and absorption heat pumps and subcategories of those. Take a look at hat pump as an alternative energy home heating option. You may find one that is best for you  - and the planet. Tell us how we can help: energymasc@gmail.com.

The author gratefully acknowledges the help for this article provided by Ryan Matley of the Rocky Mountain Institute, Chris Williams of Heat Spring and Christian Bracy.

4 comments:

  1. I think heat pumps should be used as a last resort. Insulation, and ventilation should be first used. After that, for heat, vacuum glass tubes should be considered to gather heat, and store it and distribute it as needed.
    The problem with heat pumps, is that their COP is low like 2-3, depending on the temperatures involved. But, the average efficiency of electricity generation is 30%. So for heating, why not just burn gas directly rather than messing with a heat pump?
    For cooling, most houses are not insulated properly. Insulation should be at the roof line, with ventilation in the attic, to prevent the attic from overheating. The sun directly on a building is the culprit for most heat problems. AC should be used only after shade, insulation, and ventilation are used.

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  2. Great post. The information here is something everyone should consider, especially the heating costs. In Calgary they haven't released and data like this yet. Thanks again.

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  3. @tbear - COP of 1.5 to 3 is common on a GOOD air-source application. Geothermal provide operating COPs of 4 to 6. Agree that reducing load is ALWAYS 1st, but thereafter geo #1 Delivers 4 to 6 units of heat for every renewable kw invested. It is a solar energy AMPLIFIER that accordingly pays back zero carbon electricity 4 to 5 Xs faster, AND still heats with solar on the cloudy day too!

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  4. @tbear - No question that load reduction is always job #1, but unlike air-source heat pumps, groundsource or geo heat pumps provide COPs of 4 to 6. More than 2Xs the best air-source is most extreme climates. Also, geo is the ultimate renewables AMPLIFIER. Make a kw with your solar array and deliver 5 to 6 units of heat energy on a 1 unit(kw) investment. Payback your solar 4 to 5Xs faster AND still run on sotred solar heat even when the sun isn't shining! Groundsource heat pumps are, in there most basic form, solar energy management devices. Like electric cars, geo makes best use of the smart grid the U.S. needs to get around to developing!

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