Still building and finishing my garage/shop/loft. The plan is to finish the loft as a small apartment/guest house – move in and start building the main house.
Been thinking about NOT running gas out there, but just going with a heatpump and an air handler for AC and Heat, and then an electric WH. The garage has 200A service.
Some sites say that heatpumps are ineffective in outside air temps under 40 F – I am in Wisconsin sort of “south central” area. This past winter we had 30 days below 32F. Anyone know if this is crazy to do or is it workable?
Don’t think permanent residence, but rather seasonal. We will spend one winter in their max; but it could have guests in the winter. I know that gas is the way to go for heat in the main house, and if the garage loft ever became a MIL suite we’d have to consider converting to gas. . . . However, I will want to still keep the place at 40 or 50 degrees in the winter so the pipes don’t freeze.
Not looking for sizing assistance, per se, but here are the specs so you know what kind of space it is. It’s about 800 square feet, R38 in the cathedral ceiling, R19 in the walls, R38 in the floor. The lower level has insulated garage doors (which are close to worthless), R19 in the walls. Clerestory windows facing south in the upstairs have an overhang that allows direct sunlight to enter the loft in the winter.
Thanks in advance for any opinions or insights.
Replies
It would probably be more expensive than propane, and certainly more expensive than NG, but for the use you describe it might be reasonable. Below about 30-35F the pump essentially stops working, so you use "emergency" resistive heating, meaning that the cost per BTU probably triples. But the place sounds to be well-insulated, so with a 200A service you should have no problem heating it.
Below about 30-35F the pump essentially stops working....
Not really, see the attachment, but even with low elec rates (SPI has one of the lowest rates in the country) a HP becomes more expensive than gas at about 24F in SPI. The attachment from a cost trade I did for an installation in Springfield, IL. This trade was a no-brainer, 1600 sq ft house, decent insulation, scratch and dent packaged HP off e-bay, out of pocket cost $400 after utility rebate for HP, payback in 1 year over NG. !
Factor in your actual elec rates (maybe 2X) and gas rate (maybe lower?) to get a chart for your location.
Interesting information. . .
Since HP is not the norm here, I wonder if I can get good advice on it from any contractor? I would think most would want to do the standard NG forced air system with central AC.
I wonder if my local utility has a HP rebate? I did not see it on their site, but it did say that the current rate is $0.0696/kWh
As for the supplementary resistive elec heat - is it part of the air handler or is it normally done with baseboard?
What about this - see link - (probably too expensive acq. costs for a "part time residence") I have an email into them for more info . .
http://www.steffes.com/offpeak/comfortplus/cen_pump.aspx
If I google for "Heat Pump Wisconsin" I get info about geothermal heatpumps. When we do make the move from the old house to the loft, we will have to dig about a 200' trench to tie into the sewer. I wonder if that same trench would be the right size for an "out and back" geo loop?
Lots of questions . . .It seems like a geothermal would be the best, but I am clueless on the equipment costs.
"What about this - see link - (probably too expensive acq. costs for a "part time residence") I have an email into them for more info ."
To expensive for full time residence IF you don't have special off peak rates.
You really need to contact the utility. They should have a marketing or cosnumer relation department that will give you the full blown details on any special rates, rebates, etc that they have.
If the 6.96 is the increment rate that you will be paying to run the heat pump then that drastically shifts the curve in Art's example.
But without some more research you don't know if that is the nominal rate, average rate, best incremental rate, etc.
If you dig down enough on their web site there is a good chance that they have the full details of all of the schedules. But it might take a while to find.
Edited 7/11/2004 12:02 pm ET by Bill Hartmann
Jim,
I would opt against a heat pump. I think the WI winters would be too cold. Grew up in WI, now live in VA. Many houses here have a heat pump ( self included), works o.k. I was told that where I live now, is right on the border (climate wise) for heat pumps to work efficiently.
Only 30 days below 32F???!!! You guys have a heat wave there?? Or was that 30 days in January (grin)? Dont forget about the drop in temp in night.
m2akita
What I meant by the "30" days is that the daytime temp for that period never poked above 32F. You are right, the nights were even colder. . . .
There certainly are some conflicting bits of advice here. . .
"Been thinking about NOT running gas out there, but just going with a heatpump and an air handler for AC and Heat, and then an electric WH. The garage has 200A service.
Some sites say that heatpumps are ineffective in outside air temps under 40 F - I am in Wisconsin sort of "south central" area. This past winter we had 30 days below 32F. Anyone know if this is crazy to do or is it workable?"
Jim
Workable? Yes. Crazy, yes. I lived in a 900sq' ft condo in Madison that had a heat pump. Very well insulated building, and our heating bills were $300/month! back in the late 80's and MG&E had pretty low rates back then).
Currently, I live in an "on the top of a very windy hill" 1920's 2400sq/ft cape in SE WI which rarely see's a bill above $200/month on NG in the dead of winter (-80 wind chill at times) and we keep the place at 73F., Propane is even cheaper. Especially for HW. Easily half the price/year vs electric.
Edited 7/11/2004 2:57 pm ET by WorkshopJon
Hi Jon,
Part of the problem is, compared to the local electric utility, WE (our NG provider) is harder to deal with. Since the plan is to tear down the house, I want to get the garage as "up and running" as possible before that day. I have a separate meter on the garage and electrical installs have progressed nicely. WE does not want to give me a second meter and the current meter is attached to the house. I am concerned that there will be "logistical" problems getting them to move that meter in a timely manner.
In the long run, gas is definitely the best choice. However, I will try to do some more research on Geothermal heatpumps before resigning myself to that fact.
Didn't realize that was you Jim. For temporary heat out here, I think propane is the way to go (that's what I'm going to put in my accessory building/workshop) Cheap and portable.
Currently those 100lbs cylinders can be acquired for free from any gas supplier, and filled for $37.00 the last time I exchanged them. The heater (forced air) and regulator shouldn't't set you back more than a few C notes.
Jon
Edited 7/13/2004 4:45 pm ET by WorkshopJon
I have thought about that, too. (propane) My thought was that I'd get a nat gas furnace with the propane conversion kit. After the house was done and had its meter re-connected, I could be ready with a pipe running to the garage, convert back, etc etc. . .
I have no clue about propane consumption. How much time you think I'd get on a 100lb bottle over the winter (with two people living in the loft). A day, a week, a month?
Then I just need to decide what to do on the water heater - same conversion process, first elec, point of use. . . . Can you tell I'm not in a rush?
"I have no clue about propane consumption. How much time you think I'd get on a 100lb bottle over the winter (with two people living in the loft). A day, a week, a month?"
Jim,
Don't know about heat, but for showers(HW), a clothes dryer, and cooktop, 2 people every day, 100LBS/ every 3 to 4 months. Basically 4 cylinders/year.
Jon
I think I am going to get a High-Eff forced air furnace and a propane conversion kit from these guys http://www.alpinehomeair.com
It sounds like a 100lb bottle and a back-up of some sort will probably do the trick.
Can you find someone who already has the set up in question?
I assume you mean a set up like the geothermal. No, I don't know of anyone with that set up. I imagine that I could call around, though.
Do you know anyone on a geothermal system?
yes, in so carolina not where you are.
my take was always that they were so expensive that the payback was too long. (air to air was cheaper and quicker to install, but air to air might not work where you are)
>I will try to do some more research on Geothermal heatpumps before resigning
I have a feeling the water-source guys don't want anyone to buy their products (i.e. water furnace, climate master). $1500 for the unit, which is far simpler mechanically than the $1000 1.5 ton heat pump unit I can get as a package with an air cooled condenser unit. Should be cheaper, b@st@rds!, than a darned air cooled unit with a separate furnace and condenser!
then if vertical 300' well for the 1.5 tons, filled with bentonite for heat transfer, piping, and an added premium on the water source unit if you want the pump built into it.
remodeler
I only have one quote so far. It was $2100 for a 1.5 ton. I like your prices better. I know what you mean though. Economy of scale, I suppose. They'd be cheaper if more people used them if they were cheaper. . .
I have to dig a 150' trench from the garage to where I will tie into the sewer. It will be at 4' at the garage and 9' at the sewer line. I was thinking that I could have it dug extra wide and use that (or extend it) and do a surface loop (the overlapped loop style - looks like a splayed out slinky).
We'll see, like I said to Jon - I have lots of time to think about it. This project has been going on for quite a while and I am just now doing the plumbing. . . . .