Radiant heating system in an old home -- is it wise?

Brad White_9

Sheila-

First order of business is to tighten up the building envelope which I am sure you know. Given that the house is 200 years old you probably have already explored that at this point. Do we agree on that? You may not have enough space/cavity to insulate; I can appreciate that.

The person you spoke to about not having a house breathe with radiant heat is confusing issues it seems to me. Radiant heat has nothing to do with the house breathing. Seems your house may be breathing too much as a function of it's very construction. Your source may be thinking of radiant in concert with ultra-tight modern construction.

Here are some thoughts:

1) Have as detailed a heat loss calculation performed on your house as you can. You will need this regardless of what system you choose.

2) Older homes, unless you are planning major renovation, are limited in application of radiant floors: Staple up is common but old framing can be irregular as an understatement. A competent professional company should see the place for themselves and help you decide. Top of floor applications may work but you will be replacing wide planks most likely... every old house is different.

3) You may find that your heat loss, as well as your house can be insulated and sealed, is higher than a radiant heated floor can support. Older uninsulated houses in my experience can have heat loss ratios as high as 60 BTU's per hour (BTUH) per SF or more. Radiant floors have a comfort limit of about 35 BTUH per SF.
But radiant effect on the body can compensate for the effect of inadequate insulation to a degree; you can feel more comfortable at lower temperatures.

What I am suggesting is that you explore floor radiant or even wall radiant (both with insulation below or behind them respectively) and see how far that takes you toward meeting your heat loss. Then supplement with radiant panels or good old cast iron.

If the radiant aspects do not work for you, the panels or cast iron radiators are a great way to go, IMHO.

Hope this helps.

Brad

sheila sullivan

Radiant Heat in an Old Home

We have decided to upgrade the heating system in our 200 year old home
from baseboard heat to radiant floor heat. There is a lot of draft in the house
due to inadequate insulation and single pane windows.

We just spoke with someone who has radiant heat in their old home and they
mentioned problems with the house not being able to breathe.

Is this true? What would be our best choice with heating? We opted not to use
hydro air because of the noise and the inconsistency of heat.

jalcoplumb_2

Draft and insulation.

Spend your money first on insulating and upgrading window and doors that are drafty. Eliminate the draft then look at your heating system. Dollar to dollar this will be the best bang for your buck.

If you seal the house up and have no fresh air exchange then you can have other problems. You should make sure you install an air-to-air heat exchanger to allow for fresh air to be introduced into you home.

Once you insulate and tighten up the structure you should then do an accurate heat-loss analysis to determine you heat requirements. If you do a heat-loss prior to insulating you will end up with a heating system that is oversized for your house.

I see a lot of folks that update the heating plant before insulating in hopes to reduce energy cost. When they don’t see a big savings then they insulate. By insulating they then reduce the heating requirement for the home and end up with an oversized boiler, which ends up costing more in fuel because it short cycles.

After updating the structure then do your heat-loss. Then examine your existing system. Is it oversized? Is there enough radiation? Is it piped properly? Are there a lot of zones that can cause short cycling of the system? Is it comfortable and you don’t want to update it now?

Size the boiler and installed radiation based on the heat-loss analysis. Whether you do radiant or keep your baseboard you should end up with a very comfortable and energy efficient home.

jalcoplumb_2

Draft and insulation.

Spend your money first on insulating and upgrading window and doors that are drafty. Eliminate the draft then look at your heating system. Dollar to dollar insulating and new windows/doors will be the best bang for your buck.

If you seal the house up and have no fresh air exchange then you can have other problems. You should make sure you install an air-to-air heat exchanger to allow for fresh air to be introduced into you home.

Once you insulate and tighten up the structure you should then do an accurate heat-loss analysis to determine you heat requirements. If you do a heat-loss prior to insulating you will end up with a heating system that is oversized for your house.

I see a lot of folks that update the heating plant before insulating in hopes to reduce energy cost. When they don’t see a big savings then they insulate. By insulating they then reduce the heating requirement for the home and end up with an oversized boiler, which ends up costing more in fuel because it short cycles.

After updating the structure then do your heat-loss. Then examine your existing system. Is it oversized? Is there enough radiation? Is it piped properly? Are there a lot of zones that can cause short cycling of the system? Is it comfortable and you don’t want to update it now?

Size the boiler and installed radiation based on the heat-loss analysis. Whether you do radiant or keep your baseboard you should end up with a very comfortable and energy efficient home.

Mad Dog_2

couldn't have said it any better than Brad......................

and I will add. It would really behoove you to get a heating pro in there for the heatloss and design - irrespective of the type of heat you choose. The best pros in the business are right here at Find A Professional at the top. Sounds like a very interesting job, do you know the history of the home? Where is it located? Mad Dog

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Aqueous

Old House

If you do your homework and take the advice of some of the best in the industry (The Wallies) you could have a very excellent choice with in floor heat.

As is stated here improve the heat loss first with insulation, better windows, doors etc. Then find a competant designer with a proven track record (usually quality installers do great design or have access to designers of quality in-floor systems).

Next take into consideration the fact that old homes contain great thermal mass, which in-floor systems warm and they stay warm even if the air is temporarily cooled.In floor heats objects not the air like warm air heat tends to do.

The first step you have already taken by posting on this great site. I have posted only several times due to time costraints but will be a regular visitor now that I am reaching retirement age.

Dan Holohan and his followers are the best in the business. They not only offer sound hydronic and steam heating advice, they are ethical and truly committed to the industry.

Good luck and hopefully many warm feelings!

Mike T., Swampeast MO

I'll agree with everything said previously with one exception: I would NOT replace the windows instead renovating the originals and installing good exterior storms. Heat loss programs and good studies by the likes of Brookhaven National Laboratory agree that original wood windows in good shape and with storms are at least as (and likely a bit more) efficent than nearly any "replacement" window.

Cost of renovation will be similar to replacement if done professionally. If DIY, cost will be much lower and such is an ideal project for anyone with patience and basic skills. If you DIY, I highly recommend the book Working Windows.

Retrofitting radiant floors into an entire old home can be extremely expensive and/or highly disruptive. The generally higher heat loss due to construction and abundant large windows combined with floors that may well be multi-layered and quite thick can make it impractical or impossible to efficiently heat solely via the floors. A combination of radiant floors and radiators (I'd consider cast iron from salvage if at all possible) may well prove much more cost-effective and significantly more efficient while maintaining very high comfort.

S Ebels

Re heating This Old House

I live in an old house, for my area at least. There were no houses here 200 years ago. Period.

When I moved (back) in 12 years ago, it was my parent's house and the house I grew up in, it had a coal, converted to oil, converted to natural gas furnace in it. The ductwork was a mess with some rooms just right, some cold, some hot. The house had been through 2 major remodels and the heating system just wasn't doin it. So being in the trade, it was a natural challenge.

Doing all radiant wasn't practical from a construction point of view or financially so I built a hybrid. I used Climate Panel from Viega to do radiant in the living room, heated the rest of the main level with Radson steel panel radiators controlled with TRV's and ran plain old Baseboard in the second level. The plan for this summer is to install some old cast iron radiators in the basement after finishin the remodel down there. The furnace was replaced with a Viessmann Vitola boiler which provides two water temperatures and makes all the Dhw for the house via an indirect water heater.

As Brad said, whoever told you that their radiant system makes the house unable to breath is confusing issues. What they are probably thinking, and I've heard it many times myself, is that by not having a furnace or air handler blowing air around, the house isn't "breathing". The fact that your heating system doesn't blow air has nothing to do with ventilation. They are really two different issues and should be addressed as such. Moving air doesn't automatically equate with ventilation. It's really another field and topic by its self.

Best advise I can give you is to procure the services of a good HVAC guy who is famiiar with hydronic systems of all types and consult with him as to what is best for your house. If you can find someone here from the Wall you're in luck. We have an unspoken standard here that basically says each job we do has to be better than the last one.

Educate yourself by reading some of Dan's books and hang here for a while. You will learn what to look for in a contractor and what can and can't be done in your house.

Enjoying the process will ensure that you enjoy the results.