Gas Fired Heat Pump - viable alternative to a new gas boiler in 8 unit condo in North Jersey?

March 6, 2009 5:47 AM

The ancient oil boiler in our 8 unit condo needs to be replaced and we are exploring the options, specifically gas fired heat pumps.

Electric heat pumps have been around since the 80s and don't tend to work well in places with sustained cold such as here in Jersey City. But there seems to be some buzz about gas fired heat pumps.

I know oil prices are relatively low now and I guess a lot depends on future prices (personally I think they're going to go up substantially) but I was wondering if anyone has strong opinions for or against gas fired heat pumps? Specifically what are the deciding factors when evaluating this solution: price of gas, cost of maintenance, cost of installation, running costs, opportunity cost (ie. new gas boiler), life expectancy, federal and state subsidies...am i missing anything?

The heat pump will apparently lower our carbon emissions but i'm tending to think its wiser to let the technology mature. That said installing a new gas boiler is a very long term alternative. Wonder what comparable climate countries such as the Germans are doing about this.

Cheers - JoC

posted by lapsang to Home & Garden (5 answers total)

One thing you seem to be missing is whether or not you currently have a gas hookup. Because if you don't, getting one installed could be quite expensive. It's entirely possible that your neighborhood doesn't have the infrastructure. For many people, this winds up determining what kind of heater they wind up getting, because not everyone can use every type.

If you've got it though, natural gas (I assume that's what you're referring to) is about the cleanest fossil fuel you can burn and tends to be pretty cheap.

Something you might consider is a geothermal, aka "ground source" heat pump. It's basically a modification of the standard electric heat pump, but rather than using the ambient atmosphere as the exchange medium it uses groundwater. This improves efficiency for two main reasons. First, groundwater is always in the 45-50F range, so it's warmer than the outside air in the winter and cooler than the outside air in the summer. This means that your source of heat or sink for heat is a lot closer to where you want it to be, so rather than heating/cooling air 30-50F, you've only got 20-30F to go. But second, water holds a lot more heat than air does, so the rate at which you can heat/cool goes way up. Trying to dump extra heat into air that's already 90F takes a lot of power. Likewise, squeezing heat out of air that's below freezing does too. But if you can warm up the air from 10F to 50F using groundwater (or cool it from 90F to 50F) before using an electric heater (or air conditioner) to bump it that extra 15-20F, that's going to save you a lot of money. My parents added about 35% to the floor space of their house a number of years ago and switched to a geothermal pump at the same time; their electric bill was flat.

The downside to geothermal units is that you need some space to install them, and the installation itself isn't cheap: $10,000 easy. But your use of utilities is drastically reduced, so this may well be the "greenest" option available to most people.
posted by valkyryn at 6:37 AM on March 6, 2009

Gas fired heat pumps are relatively new, although the technology has been around for awhile, so it's probably wise to wait. Geothermal seems to be the most mature technology that fits your needs.

Also, congress reauthorized the <>energy efficiency tax credits , so you might want to look there as well for ideas.

So, you said boiler, does your building use steam or hot water?
posted by electroboy at 7:37 AM on March 6, 2009

Oops, link is here.
posted by electroboy at 7:38 AM on March 6, 2009

To what does this ancient boiler feed hot water (or steam)?

To me, a heat pump to provide hot water would make sense when considering a ground-source heat pump (somewhat confusingly called geothermal) but otherwise, if you have natural gas available, I would first consider a new, high efficiency gas boiler.

If you are really looking to reduce your carbon emissions, schedule an energy audit for the property and reduce heat loss (go beyond insulation values here, infiltration is a *much* bigger loss). An improved building envelope will contribute further toward efficiency than any selection in your system.
posted by Dick Paris at 7:47 AM on March 6, 2009

You might consider a new high efficiency gas or oil boiler. Your old boiler was likely only 55% to 60% efficient. A new gas or oil boiler can be 85% efficient. The more efficient boiler will save you approximately a third on your fuel bill and cost a lot less than a heat pump.
posted by JackFlash at 10:04 AM on March 6, 2009