"We need a new A/C and oil furnace."
Column #838 03/19/2011
On The Level
Q. We need to replace an aging electric hot water heater, and are considering one of the new electric hybrid models that are supposed to be the most energy efficient. What do you know about the actual energy efficiency, and the validity of the test data available on the internet? We do not have the option of using a gas-fired model, unless we want to go to significant expense to install a propane tank. Of course if we did install the tank, we then could upgrade our aging furnace with a gas-fired model, rather than an oil-burner, but I doubt that expense would be worth it.
Also, we need to replace one of our A/C units, and since that unit uses the same air handler as the oil furnace (which is probably 30+ years old), the contractors have suggested installing a split system with a high-efficiency heat pump replacing the A/C. They have proposed replacing the old furnace with a new oil-burning furnace at the same time. The current furnace seems to be working fine, and replacing the furnace would be about half the cost of the job, but the contractors think we would get a "cleaner" install if we replace both at the same time. Are there any advantages (besides convenience, and possible tax credits) to waiting until the old furnace dies before replacing it, and just replacing the A/C with a heat pump?
A. The hybrid water heaters I’ve looked at have electric heating elements in them just like the old fashioned electric water heaters of the last more than half century but combines it with a small heat pump. A compressor and evaporator are integrated into the electric water heater unit and draws in ambient heat from surrounding air using variable speed fans. Condenser coils wrap the tank all the way to the bottom to transfer this heat into the tank and heat the water. Very modern.
The units generally come with a 10 year limited warranty. Read the fine print to see what “limited” means on the warranty but my guess is that if it lasts at least to the warranty period the $1,700. or so price tag is worth it. Throw a couple of hundred more bucks at the project for installation then take the advertised claims of $320. a year in electric bill savings and do the math. I get about six to eight years to the break even point after which you can argue it’s making you money in reduced electrical usage. Even if the heat pump feature dies on you, the electric heater elements will still provide you with hot water. The units come with controls so you’ll have the option of a variety of operational settings.
As for an initial tax break what I’ve seen claims that you can, depending upon your circumstances, get up to a $450. tax credit and the manufacturers will supply you with the necessary paperwork to substantiate your tax claim.
As for your old oil furnace, if it’s really the age of the house and is thirty plus years it’s time for that beast to go. It’s burning expensive fuel and hurling 30 to 40 percent of the heat right up the flue. Look at the size of the flue. It’s probably eight inches in diameter and can handle a lot of hot flue gasses. Also the nozzle that shoots oil into the burn chamber is rated in gallons per hour of burn and I’ll bet it’s rated at over a gallon and a half per hour. Furnaces like that give me heartburn just to hear them fire up. The contractors who have been advising you to get rid of it, even though they have a dog in the fight, are advising in your best long term interest.
The notion of installing a heat pump and putting that in series with a state-of-the art high-efficiency oil burner creating what’s known as a dual-fuel system has a great deal of attraction for me from both an energy efficiency and comfort point of view. The installers of such a system have to be very sophisticated and knowledgeable concerning the setting up and linking sensors and controls of such as system so you, the end user, can operate it sensibly. I’ve seen very nice serial systems poorly linked that did no one much good. Ask the potential installer if they have done it before and if so, where. Then contact those customers for a review. People love to talk about their houses and work done for them.
While you’re at it do a quick energy audit of your house and pay close attention to attic insulation-- you want R-38 up there and they didn’t do that 30 years ago-- and window and door weatherstripping. It would do you well to have the system up and running before the first 90º day comes along-- and that’s not far off.
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