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 | kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon 
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2004-01-03 72982
We are having a LOT of snow for this area, and we've had a half dozen power outages of 6-8 hours so far this year. It gets mighty cold sometimes and the two fireplaces aren't cutting it. Our 13kw genset will run everything we need except the heatpump, and it would cost maybe $8-10k to install one large enough to power that.
I was thinking of retrofitting a radiant floor system on the main floor of our house, heated by the propane hot water heater. A number of companies advertise these (radiantec comes to mind). Most of our main floor is wood so we don't have to deal with the insulating characteristics of carpet, and the basement ceiling is fully accessible. They claim you don't need a heat exchanger but I'd install one anyway to insure the safety of our potable water.
I'm interested in knowing if anyone has used one of these sytems and, if so, what your experiences were.
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 | JParker
Join Date: Oct 2003 Posts: 152 Richmond, VA 
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2004-01-03 72996
I have designed a few radiant flooring systems, mainly in new constuction. These have always been fed from the boiler system, not the domestic hot water system; however, the water temperatures would be fairly close to optimum for a radiant floor system so it might work .
I agree with your concern about circulating the domestic water directly through the floor piping, mainly because of stagnant water sitting there and then being re-circulated to your domestic hot water tank. A potable water heat exchanger would help with that by reducing the volume of stagnant potable water. The system could incorporate a timer to circulate the domestic side occasionally and minimize this problem in the off season. Stagnant water can be a breeding ground for bad things including Legionella.
Be sure to use a piping material designed for this type of service such as PEX (cross-linked polyethylene). We usually specify the piping to also include an oxygen barrier to prevent entry of oxygen through the piping. This is important if there are any ferrous metal components in the system; however, may not be needed in your application.
One of the major equipment and material manufacturers for this type of system is Wirsbo.
Most of our experience has been with piping embedded in a gypcrete or lightweight concrete slab. I have seen but not used systems that snap the tubing into a sheet metal plate installed under wood floors. That type system may be adaptable to a retrofit installation.
Does your water heater have the required heating capacity? It probably is, but just something to check.
You said the generator couldn’t run your heatpump. Is it a split system? Could the generator run the fan portion of the indoor unit? If so, you could install a hot water coil in the ductwork, and run the fan and a small pump on generator power. This is sometimes done around here as the normal source of heat where natural gas is available. See http://www.apollohydroheat.com This could become your normal aux heating system depending on electrical vs. propane cost in your area. When on generator power, since there is no power to the outdoor unit, the space temperature would continue to fall (usually only one or two degrees) until there is a call for aux heat, then the pump would start and you have heat.
If you are wired with a generator panel, put the indoor unit and pump on the generator panel, and the outdoor unit on the normal power panel. If you keep the existing strip heaters, put them on the normal power panel, and add a toggle switch somewhere to determine which aux heating system to use electric strip or hot water.
One last thought, check the size of your existing strip heater. It may be small enough to run from the generator since there is no compressor starting in rush current to deal with. 13 kw is a pretty good sized generator around here for a house. In emergency mode, many get along with 5kw units.
Hope this wasn’t an over kill answer.
- JParker
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-03 72997
Thanks, JParker, not an overkill answer at all. The heatpump is a 6 ton three zone geothermal unit with a 14.4/19.2 KW strip heater as aux third stage heat. There are three separate disconnects on the unit and one of them serves the fan only (I think).
I hadn't thought about a hot water coil - that's an idea. The difficulty as I see it is that the entire heatpump is in the basement wedged between the basement floor and ceiling. The supply duct goes through a chase to the attic and branches off, and it's all framed in so it would be hard to get to. The return air comes out the basement ceiling and passes through three filters (EAC, media, and UV) so there isn't much room for a coil there either. Still, it's an intriguing idea. I'm having a guy out to purge our geothermal loop and I'll ask him what he thinks.
Companies like Radiantec push using the hot water heater as the hot water source. Our hot water heater is a HUGE 90-100 gallon Bradford-white unit that has a very fast recovery rate so it might work. If not we could always plumb in a small boiler (which would double the expense of the system). They sell these systems as retrofit using the sheet metal reflectors under the subfloor. I'm not sure how well these work though. I suspect I could do this for a couple of thousand bucks, which would be quite economical compared to a new genset.
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| JParker
Join Date: Oct 2003 Posts: 152 Richmond, VA
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2004-01-03 73000
So much for the little strip heater concept.
No problem, as much as I have learned from the people on this board, its the least I could do.
Geothermal HP, great to hear. I really like those, very efficient when done right.
Horizontal or Vertical?
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-03 73001
It's a vertical WaterFurnace unit.
Actually, I hate it. Not only has it been unreliable, but it uses double the KW power than WaterFurnaces projections said it would. I log the consumption of each circuit feeding the unit and I know exactly what it uses, and WaterFurnace was way, way off.
Yes, we are using less than others in the area with similar sized homes but due to their erroneous projections the payback will never be realized. And the system is installed correctly - we've had three other contractors out looking at it and they have found no problems. Plus, we've had blower door tests (the house is tight with a 0.28 ACH) and duct pressurization and sealing tests. ....
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| JParker
Join Date: Oct 2003 Posts: 152 Richmond, VA
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2004-01-03 73003
Sorry, I meant the ground exchanger. Is it vertical wells or horizontal trenches.
Based on the problems you mentioned, and the fact that this is very unusual from our experience with geothermal, I would like to get more details if you are interested in an opinion from an informed 3rd party.
If so, please drop me an e-mail.
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-03 73005
We have a horizontal loop.
It's very generous of you to offer advice. I'm sort of at my wits end on this, so I could use an informed third party opinion. I'll put together some information and send it to you. Your profile doesn't list your email address but if you send a blank email to me (ken at qsolv dot com) I'll have it. I really, really appreciate it.
I sent a letter to the president of WaterFurnace, explained our situation, sent them copies of their energy consumption estimate vs. measured consumption numbers, and offered to pay half the expenses if they'd send a tech out to evaluate the system and they refused. Our dealer dropped them due to excessive warranty claims and insufficient warranty reimbursement. I think they're a crappy company. ....
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| JParker
Join Date: Oct 2003 Posts: 152 Richmond, VA
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2004-01-03 73006
Sorry, I though it was in my profile.
I sent you one just after my book was posted, and am working on a second with a few questions you may need to look up. ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-03 73008
Thanks, John, your email was trapped by my spam filter but I got it and whitelisted your name. If you get a bounce notice just ignore it.
Thanks,
Ken ....
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 | blizzard
Join Date: Jul 2003 Posts: 282 Central Maine
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2004-01-04 73009
Ken, It might be easier and more comfortable to install 1 or 2 direct-vent propane heaters with millivolt (self-powered) thermostats. You have the propane, your outages seem to be relatively short, and an electric-free backup would allow worry-free winter vacations. During the 1998 ice storm I put a 35,000 BTU Empire unit in my garage to prevent freeze-up. Was so happy with it I added another smaller unit upstairs last year.
These are not high-tech heaters, but they are inexpensive, reliable, easy to install, and do keep you warm with absolutely no electricity!
Just my 2cents, but a radiant project is.... a PROJECT.
Fireplaces become less efficient as the temperature plunges, though they make the room cheery....
bliz ....
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 | Billy
Join Date: Oct 1999 Posts: 975 Southeast Oklahoma 
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2004-01-04 73017
Ken
We have a fireplace but I blocked the chimney off and put in propane vent free gas logs.
Our house is 3,500 sq ft and the logs heats it pretty good. When it's really cold, the heat pump for the back part of the house will run on occasion. The heat pump for the front part of the house doesn't come on all winter.
A couple of years ago, we had an ice storm and was out of power for 9 days. Sure glad we had those gas logs.
Billy
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 | Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2004-01-04 73021
Ken;
I also put in a geothermal system. For back up I have a pellet stove. Modern pellet stoves are quite efficient and also have the self light feature. With the costs of the pellets I can heat 4000 sq ft for about 2 dollars a day. I like the idea as I have no flue except a small vent out the stone wall.
I have a outside wood water heater and thought about the radiant system as a back up but the cost slowed me down. I also looked at the in plenum option and the coils are in the 900$ range. I still have not ruled this option out as the outside wood boiler is unused at present. ....
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 | AC5ZO
Join Date: Jul 2003 Posts: 928 Rio Rancho, NM 87144
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2004-01-04 73023
Ken, I have hot water floor heat in my house. It is very confortable to have the floors warm, but will probably want to have a number of heating zones to keep from overheating some interior rooms. This is done with thermostats controlling hot water solenoid valves. I have six or eight zones in my house.
I use a separate hot water boiler for my heating. With having some heating zones that might be off, the original warning about stagnant water in the heating system is a good one. I would not want that stagnant water in my regular hot water since I use well water and it is not treated with any chlorine or anything like that. ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-04 73033
Thanks, guys, for all the good suggestions.
Blizzard, I hadn't considered direct-vent propane heaters. Are those the wall-mount heaters? One problem is that for such a big house we have an incredible lack of available exterior wall space. We have a lot of floor-to-ceiling windows in all living areas. Might be able to put them in one or two bedrooms or the basement, though, and circulate some air. I know what you mean about in-floor heat being a project. I'm not sure it would be a whole lot worse than trying to get propane to the bedrooms though :)
Billy, when we built we plumbed and stubbed out gas to both fireplaces. Do gas logs put out that much more heat? When we stoke the fires with wood and turn on the circulation fans (generator powered) it feels like we get a lot of heat out of them, just not quite enough to keep the whole above 60 degrees. Of course in-floor heat in the main floor won't heat the bedrooms either.
Peters, a pellet stove sounds good but again a lack of wall space would limit where we could locate it. The hearths are raised and are too short to hold a stove. Our neighbor has one and doesn't like it and I sort of dismissed the idea due to that. Maybe he just doesn't like the fact that it doesn't work when power is out. It seems it would be convenient auxiliary heat though. A hot water coil in the supply air would probably be cheaper, assuming we could run it off the water heater.
AC, if we do the radiant floor it will only be done in the living spaces on the main floor. Maybe two zones at most. You have reaffirmed my desire for a heat exchanger - we're on a well too with no chemical treatment. Our main living space is vaulted and we have problems with stratification anyway, so in-floor makes sense from that perspective. ....
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| Billy
Join Date: Oct 1999 Posts: 975 Southeast Oklahoma
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2004-01-04 73034
Ken
Since my chimney is blocked off, ALL the heat from the logs stays in the house. It looks just like real logs burning. Pic #4 ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-04 73037
Gotcha, Billy. I didn't think about "vent-free" when I read it. There are no combustion by-products to worry about?
Beautiful fireplace by the way - love the stonework and the curved hearth. I won't show it to my wife :) ....
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| blizzard
Join Date: Jul 2003 Posts: 282 Central Maine
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2004-01-05 73075
Ken,
Yes, the heaters I referred to must be mounted on an exterior wall, the center of the vent 16" or more from any outside obstruction or corner. There are many 'modern' (efficient) propane units, but for my application I needed a vented, thermostaticly controlled, electricity independent heater. That effectively eliminated anything with a pump, circulating fan, or modern combustion chamber technology.
It seems you have less restrictions, good luck with whichever method you choose.
bliz
PS- you may want to look here. Lots of info on heat exchangers, solar heating, off grid living, etc.. ....
Link: homepower
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| blizzard
Join Date: Jul 2003 Posts: 282 Central Maine
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2004-01-05 73076
Ken,
FYI, from my (limited) experience, the catalytic radiant propane heaters are odor-free, the blue-flame type (unvented) not completely so.
No problems with smoke detectors with either, so long as the air near the detector is below about 105F :)
bliz
More specific link for heat exchanger- ....
Link: heatexchanger
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 | Murf
Join Date: Dec 1999 Posts: 7249 Toronto Area, Ontario, Canada
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2004-01-05 73105
Ken, if you are thinking of adding radiant coils as occaisional heat only I would add a word of caution which would probably not be a concern if it is full-time heat.
When you are adding radiant coils beneath a WOOD floor you heat the wood before anything else, this means you will drive the moisture out the wood when the heat first comes on. Conversely, as soon as the heat is removed the drying stops and the absorbtion begins again. If this only occurs at the beginning of the heating season it is not as much of a concern.
If however it happens on a more frequent basis you may experience some prblems with warping, checking and finishes, especially hard clear coatings, cracking or peeling. If it continues for any length of time it can lead to excessively large spaces in the joints and an increase in the squeaks and noises when someone walks across it.
Best of luck. ....
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-05 73110
Blizzard, thanks for the links and info. I need to do more research on the propane heaters or log sets, it sounds promising.
We were actually thinking of retrofitting radiant floor heat on our main floor anyway, and using it as emergency heat was an afterthought. Our main living area is vaulted with a 24 foot ceiling and it's hard to keep it comfortable, so in-floor heating seemed like just the ticket. Then the snow fell and it clicked that it could provide some heat when the power is out as well. If we went that route it would provide heat all winter, not just when the power goes out so cycling of the wood floor shouldn't be an issue.
The best setup might be a combination of in-floor and auxiliary heaters (heatpump most of the time and gas heat when power is out). Not all of our outages are short - it was out for a week last year. ....
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| Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2004-01-05 73118
Murf;
One of the reasons that I pulled back from the under floor retro fit systems (the area I was considering has marble tile) Is that I would dry out the plywood. Depending on the type of wood on the floor the system could really do some damage.
I have room for the heat exchanger on the heat pump and therefore was considering this system. The old house had it set up this way and it was comfortable.
Ken;
I have the 24 foot sealings also but have a fan at the top. I don't find the room much different than the rest of the house.
The pellet stoves have improved yearly. The unit I have is far less effecient than the new system. I have my system in the basement and run it through the wall as it is a walk out on that side. There are a number of options.
The propane is an option although the only propane I have is for the gas stove top. I really did not want a large tank just for occasional work.
My heat pump also heats the domestic hot water and therefore have two separate tanks. As the heat pump heats the water most of the time I have only electric tank to keep the second tank warm after heating.
Eric
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-05 73126
Eric, I've heard conflicting stories of problems with underfloor radiant heat on wood floors. It's confusing and hard to know if there's a legitimate problem or not. I figure that heating the floor to some moderate temperature, like 60-65 degrees, and using the heatpump to make up the difference may minimize any problems.
We also have a ceiling fan on a 10-foot downrod in our vaulted area. The fan helps a lot but there's still a 2-3 degree temperature gradiant floor-to-ceiling. Our heatpump also has a desuperheater to provide hot water but I turn that pump off in the winter since heatpumps heating performance is already marginal. We use propane for the cooktop, water heater, dryer, generator, and have it stubbed out to our fireplaces and outdoor future hottub.
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| Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2004-01-05 73174
Mean ground temperature is 60 degrees here so the basement is always that temperature anyways. With the pellet stove in the basement this may make the difference in the front room. I have seen little difference in the upstair and down stairs temp in the winter or summer. I have the fan on a 4 ft rod is it possible that you are not pulling the air from the ceiling properly?
I did not go for the superdeheat on the geothermal. It only heats the tank when it is on. ....
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| JParker
Join Date: Oct 2003 Posts: 152 Richmond, VA
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2004-01-05 73178
I'm still interested in de-bugging that Geo if you are. Check today's e-mail for shorter list of questions.
I admit to tunnel vision on the bigger picture. Although I am not a fan of any unvented heater, I agree that unvented logs or even a wall heater would do well for occasional use. The wall heater could go on an interior wall. Just not in small areas or bedrooms (check local codes...). I would also add battery powered carbon monoxide detectors as added safety if you don't already have them. ....
Link: Northern Tool - Unvented Propane Heater
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| kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-05 73179
We have 7-8 sf of return air vents at the peak of our vault so that pulls hot air from the vault ceiling and recirculates it. I know that works 'cause I have to vacuum the registers all the time :) We run with continuous fan to even out the temps and better filter the air (wifes allergies).
How do you heat the tank without desuperheat? ....
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| Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2004-01-05 73190
I used the Nordic system it heat but does not turn on only to heat the tank. When the system is on it heats it does not come on just to heat the tank. ....
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