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To heat pump or not?

Posted by krustyoldhouse (My Page) on
Mon, Nov 29, 10 at 22:45

I have a two-story farmhouse built in 1899. It currently has an oil furnace with forced air duct work that only serves the first floor. Warm air is supposed to find its way up the stairs to the bedrooms. The old ducts are larger and the air seems to blow a little harder in an effort to make the second floor warm. It doesn't really work and the 1980's furnace is on its last legs. I brought in a HVAC guy who said, "We'll put a heat pump in the basement for the first floor and another heat pump in the attic for the second floor, $40K or more."

That's not going to happen, but I would like to get away from oil heat and I plan to install task heating in the second floor rooms that need it, but I am wondering if anyone is successfully using a heat pump to heat a two story house ducted in the manner I described? I just don't believe heat pumps, even the newer ones with heating elements, can make air warm enough to carry sufficient heat to the 2nd floor.


Follow-Up Postings:

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RE: To heat pump or not?

Where you live will determine whether a heat pump is even a viable alternative to forced air. Why not go hot water heat? Do you have access to gas or propane? That was our choice for our 1820s house, because there was no way I was going to carve out floors for ducting. It is quiet, has very even and gentle heat and there is no rushing hot air to dry out the atmosphere or wood. Our cost for two stories? Less than ten thousand installed.


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RE: To heat pump or not?

Our house was like that. We live in NC, so heat pumps are a decent option here. We went with a gas furnace for the lower level and a heat pump for the upper level. The attic placement meant we didn't have to damage any interior structures. They just cut holes in the ceiling where the vents went and that was it.

The $40k sounds way out of line though. Ours cost about $18k total for both systems - including AC for both levels.

BTW - we did this 2 years ago. The prior owners lived there for 50+ years with no heat in the upstairs. The attic insulation was minimal and all the windows were leaky. It was COLD!!!! up there at night.


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RE: To heat pump or not?

This house is in Maryland, but it's on a ridge and the wind does blow. The first floor ceilings have registers that were meant to let heat from the old franklin stoves (long gone) rise to the second floor but all that is marginal even with the oil furnace. I grew up in this house so I know how cold it gets upstairs, but it will come as a shock to my wife when we move in.

Naturally, we will be tightening up the insulation package and the windows.

I will use propane for the water heater and the range (and maybe a FP), but I'm not sure if it's any cheaper than oil as a heat source? I like those in-floor radiant systems.

Thanks for the replies.


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RE: To heat pump or not?

I doubt that propane will save you any cost over oil, but the propane does burn cleaner. It also makes less mess. I have yet to meet an older oil burner setup that didn't stink and have oil stains around it.

I like the fundamental idea of a heat pump - making heat out of thin air, so to speak - but my experience has been that gas furnaces are generally simplest and most trouble free, followed by oil furnaces, then by heat pumps.

I do know one person who has a GSHP ("geothermal" system), and has had zero problems with it in over 10 years. From what I read elsewhere on GW, that seems to be the exception, however.

What surprises me is that your 1980s gas furnace is "on its last legs." I own a rental house which still has its original gas furnace from 1959. The HVAC guys roll their eyes every time they have to work on it, but it keeps on blasting the heat out, year after year. That said, it probably burns quite a bit more gas per heating season than a modern high-efficiency gas furnace would.


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RE: To heat pump or not?

You should definitely do some research on the expected efficiency of any unit you plan to install, also the price per unit of fuels you have available and also how many BTUs you can expect from a unit. Costs and availability vary wildly across the country, and I can't speak for your area.

One reason I suggested boiler is that pipes are easy to conceal and run in old houses. It also means one unit does the job if the circulation pump is sized appropriately. You can also piggyback a hot water source onto it and have your hot water produced along with your heat. You cannot piggyback cooling to it, however.

My first husband was a heating and cooling engineer. I used to help take off jobs for him and I also worked in a furnace company. Years ago, and the technology has improved. I am amazed at a 40K estimate and I am sure one unit should be able to provide you with heat to both levels without having to put supplementary task heat to rooms. The joy of a boiler is that you can set it up in zones so that sections of your house you're not using can be either turned off or heated very much lower than the spaces where everyday activity occurs.

I don't know if this is true or not, but I've heard over the years oil is the least safe of fuels for furnaces. I'd be researching all your options as to different methods of heat (keeping annual fuel costs stressed) as well as multiple estimates on the same system.

I've heated with everything from wood to oil, to electric FA ad baseboard, to propane, natural gas and coal. I love my gas fired hot water heat, it is efficient, gentle and quiet with no scrub from air movement. Good luck.


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RE: To heat pump or not?

The problem with asking a contractor what to do is that he will tell you to buy what he likes to install. I design a lot of custom houses and use an HVAC designer who provides the design and specs and then we put it out to bid with several contractors.

The cheapest heat will be forced hot water to baseboard radiators from a very high-efficiency gas-fired condensing boiler but if you also want air conditioning that's what runs the cost up.

I tried to anticipate the design from my consultant but soon learned it was a waste of time and money. It is the controls that save much of the energy in modern HVAC systems so it takes a pro to do it right.


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also

You might also consider the multiple unit "ductless" heat pumps that hang up high on walls and are piped from one remote outdoor unit.


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RE: To heat pump or not?

The 1980's furnace was submerged in a plumbing flood so that's what did it in. I think the oil burner before that was from the 40's? I'm leaning toward a heat pump for the sake of the central AC, but I imagine I will need a backup system of some kind. I'll look into propane since I have it for the HWH anyway. I oftenfantasize about having a solar air or HW pre-heat system to warm the upstairs since I believe fuels in general will be priced out of the home heating market over the next ten years. I just paid $2.99/gal for oil, which is down from a couple of years ago.


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RE: To heat pump or not?

Sorry for the long post, but here is a bunch of info to digest.

Did you know there is a heating and cooling forum on Garden Web? You might cross-post there.

I work at an HVAC distributor and live in a old house myself, so here is some info to consider.

I would imagine that switching from your current system to what the dealer has proposed includes removing the current system, all new properly sized ductwork for both systems, and 2 systems themselves, and running electric to the attic, and maybe running electricity to the basement, maybe upgrading your main electrical panel to handle this load, and then fixing up your walls where this was all done. If this is the case your bid is on the high side, but not crazy. Especially if they are recommending a high end system.

But that is still a lot of money.

I also assume that your home currently has no AC, and only heat.

Do you have access to natural gas or propane? How important is adding AC? Will you homes current electrical panel support what they want to do?

Does your state or electric utility offer any programs for using electric heating? If so, find out what they are and make sure your systems qualifies.

Here in Kansas City, our power company give a $600 install credit for installing a system that meets a particular efficiency. And also gives a reduced electric rate between Oct and March. Over the summer the state was also offering credits to install efficient systems.

So even though the $1500 federal tax credit is ending after Dec 31, there are still programs that are available, but they vary by location.

FWIW, if it were my house, I would want the AC. So I think I would look at a propane furnace in the basement with a heatpump, and an air handler (which is a blower that has the cooling coil, but no heat) with electric heat strip in the attic with a heatpump. Find out if using this system 1 would work for now with your current ductwork, and also work if you later added system 2 and reworked the ducting at that time.

If you will never ever want AC, then go with a boiler.

In heating, efficience is measured by coefficient of performance. How much heat you get out vs how much energy it takes to make the heat. Running a heatpump at a mild outdoor temp (between 60 and 35) gives COP between 2 and 4 for most nice systems. Electric resistance heating-where electricity is run through a wire to make heat ( electric baseboards or electric under flooring will always be COP of 1 by the definition.) With combustion heating (gas, propane in a furnace OR running a boiler) the best possible is high 90% efficient.. So the heatpump at 45 degrees outside can be 2 to 3 times more efficient as a furnace. So the fuel advantage is that you have a choice. If propane is cheap, run the furnace, if electric is cheaper, run the heatpump.


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RE: To heat pump or not?

Thanks, Juliekcmo for all the good info.

Any kind of quote around the DC suburbs is breath-taking, at least for me. I think the guy probably didn't want to quote too low and maybe he was testing my wallet. The problem I had was that I didn't really want to heat and ac the whole house. It's just the wife and I and we only really need to heat one of the bedrooms and the bath upstairs, IMO.

AC is a must in this area. The house does have a central air unit attached to the oil furnace, but it wouldn't run the blower this past Summer so I'm not sure it's still good. The furnace guy says that the AC plumbing probably won't survive the change-over to a new furnace, so I should figure on replacing them both at the same time. The upstairs has been cooled by window units over the years. I am re-installing propane for the HWH and a few other things, so it's tempting to switch the furnace, too. If you add a propane furnace the cost for the fuel is lower. I have always had oil heat and I don't really like it, but all my furnaces have been old, cranky things. I suppose the new ones are much better.


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RE: To heat pump or not?

Hi Krusty,
With that additional info, then here is some more info for you.

I would only want a complete new matched system for your downstairs. The new refrigerant that is in current systems has different attributes than the older freon. So a new outdoor unit (AC or heatpump), indoor cooling coil, and furnace with new linesets (the copper pipe that runs the refrigerant between the outdoor and indoor units) are best. This is what a better dealer will want to do.

Using a propane kit makes it easy to do this.

Since you really don't want or need to condition all the upstairs space, then do consider only running a new full system downstairs, and adding a mini-split heatpump with electric heat to your upstairs. If your bath opens to your bedroom, you may only need 1. Or if the bath is in the hall you might get 2 of them. These systems are very efficient, and would have a much lower installed cost for you. They have very high efficiency cooling and heatpumps, and would have an electric heater for operation at outdoor temperatures too cold for the heatpump. The outdoor unit is about the size of 12x 30 x 24 high. The indoor part is mounted high on the wall, and is about 42x10 and sticks out from the wall about 8 inches. These at their simplest have no ducting, and they only have 1 electrical connection. They usually run on unit mounted thermostat with a remote, but some can take a standard wall TStat. Brands to google are EMI, Comfortstar, Sanyo, Mitsubushi. Google Mini Split heat pump.


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RE: To heat pump or not?

Thanks again.

I've seen those Mitsubushi mini-splits. Are they quiet enough for a bedroom?


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RE: To heat pump or not?

Do you have any closets in the corner of a room on the main level? I have a closet in one bedroom on the main floor where they ran the ductwork to the upstairs. From there it is in a knee attic, so well hidden and not too much damage to place the ductwork. Granted, this was done in 1953, but the two upstairs bedrooms are fed by this and maintain a good temp in the winter with the heat on. I just use door socks when it's really cold as the hallway is unheated and has 4 windows to contend with.

Otherwise, boilers might be the way to go, and certainly are the wave of the future. I have looked into heat pumps myself (on the west coast) and gotten outrageous quotes with replacing the ductwork. Without replacing the quotes are more manageable. However, my 1953 Montag oil heater works like a charm, just takes up as much space in my basement as a cadillac, so it's a catch 22 decision to replace- cost vs. space!

As for the poster who said oil heat is unsafe, it truly isn't. It won't burn unless it is vaporized, so it's quite safe. My furnace has been meticulously maintained and gently rebuilt through the years and has no oil stains, doesn't smell bad at all, and I don't have any more dust than the other old houses in my area that all have oil heat, and at last testing in September, had an 89% efficiency rating. It does go against my environmental grain to have it, but it is the last system I'm replacing on my old house because it works so well. With 2800 square feet, I just turn it on and in less than 15 minutes my house is as toasty as they come. Of course, the new windows have helped in that sense as well....

Good luck with your decision, krustyoldhouse, and please repost a follow up for those of us interested in doing this as well.


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RE: To heat pump or not?

I said it, and I've lived in a house with a forced air oil furnace. There are dangers intrinsic to all types of heating systems, and some are unique to that particular system. Oil has its own, believe me. Meticulous cleaning and inspections are necessary if you go that route. Yes, it has to be turned into vapor and that means when it is......it has to be at just the right place, at just the right time or problems can happen. I don't blame you for not replacing a well-working older unit. Some of the old heating systems were made with exquisite quality of the best materials.


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RE: To heat pump or not?

We had a heat pump in our last house,I didnt lkike it .It didnt heat very well in really cold monthsI was always cold ,here we have radiant floor heat love it.We also live in North.


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