Radiant & Forced Air

[RogerK]

Greetings, all...

I am building a house this summer with my (soon-to-be-retired) in-laws (for assisted living as they age)... We are currently discussing heating systems, and I would love to pick the collective brains of you guys (I've been lurking around this forum for some time and really find your answers informative!).

We are building in the Edmonton, Alberta, Canada area where -20 Celsius temperatures are fairly common in the winter, and -35 can happen occasionally (this approaches -35 in Farenheit as well). The house itself will be about 2000 sq. ft. on the main floor, about 1200 upstairs, plus a 2000 sq. ft. full basement (although the triple garage will occupy a fair bit of the basement). I am leaning towards radiant hydronic heating, while the father-in-law prefers forced air so that the air does not get stagnant.

The question... Which would you prefer? At this point I'm thing the best compromise would be radiant in the basement (and, by default, the garage), with some additional tubing under the front entry (as we would like ceramic in the front entry, but find it can be very cold without in-floor heating), with a furnace to heat the rest of the house. Through some research I also have been informed that a house this size would need two furnaces anyways, so I'm thinking that this would achieve the same goal.

Your comments are greatly appreciated!

Regards,

Roger.

[Rich]

Radiant heat is an excellent method of heating - it circulates air through convection (heat rises and then falls essentially circulating the air). Fans can be used to distribute air further.
The problem with radiant heat is that if it cools down very rapidly outside the radiant will take some time to catch up on the interior. So my recommendation would be a dual system like you've suggested.
The forced air can be used to give instant heat to the area until the radiant heat gets the thermal mass of the floor heated.

[roger g]

I've lived in Edmonton. Great place but too cold. Rich is right about 2 systems. Radiant floor heat is fantastic but expensive to install but cheaper to operate. You can heat the water in radiant heat by oil, gas, propane, electric and even wood. The problem with radiant heat is that it takes some time for you to feel the heat . For those days where you just want to take the chill off for a few hours in the morning or afternoon then you should have another heat source. Because in most cases you only want to take the chill off, a gas fireplace with a fan works very well. Even some electric baseboard heaters work fine for quick heat. If you want air conditioning then you will need ductwork for that anyways so you might as well put in a small furnace. Though when I lived there I never needed any a/c and didn't know anyone with a/c.

Roger

[roger g]

I just noticed that you mentioned about having 2 furnaces. It must be an Alberta thing or something because of all the years I have been in heating in Ontario I rarely if ever saw 2 furnaces in a house and we have big houses. Yours is not considered that big a house. Not small but not unusual. When I lived in Edmonton I saw 2 furnace houses all over the place especially 2 story jobs. And some of these houses I thought were small. We got cold weather in Ontario too though not like Edmonton. I really have doubts about the need for 2 furnaces. Why not one for each room if 2 is good four is better.
An air exchanger will solve any stagnant air problems and they really are a good idea.

Roger

[RogerK]

Thanks for the quick responses!

Some notes:

- The initial information I got from prowling around the recent home show here and on the 'net was that the house was too big to heat with one furnace. However, after looking at a couple of sites it seems that we should be able to get one furnace plenty big enough to heat the entire beast, but that zoning might be a useful thing as some of us prefer different levels of heat (has anyone had experience with zoning?). One of the radiant sites I went to indicated that for this size of house two furnaces were required, but I can't seem to find that site back.

- I am definately leaning towards the dual system (thanks, Rich and Roger G.), but if we were to cut costs and go to a single forced air system, is it possible to heat the garage area with the same furnace? The garage area is right below my living room, so we would not want to have it freezing cold down there. It seems to me that you would need a cold air return coming back (correct me if I'm wrong here, please!), and that a cold air return from the garage area into the living areas of the house would not be wise. I think this would also be a good indication that heating the slab with radiant might be a wise decision, as we would not need to return air back to the house with that. I've also heard that costs can be quite high for a boiler, though, so I'm not sure what all we can afford yet. I've been told by many, though, that even if you don't put the radiant heat in right away, at least put the pipes in the basement and garage slabs for possible future use.

- I've lived here for all 37 years and never had A/C (although it does get quite hot here sometimes), but the inlaws at retirement age might need it for comfort, so the ducting might prove useful.

And, for the record, it's a dry cold... :lol:

Regards, Roger.

[roger g]

Dry cold. As my nose drops off and my fingers and toes turn black I'm really concerned about whether 40 below is dry or not. When I saw that store parking lots had electric receptacles for engine heaters for their customers I knew it was going to be cold.
Over the years it looks like heating systems are getting fancier all the time. For years, zone controls were the little levers attached to every floor register. Instant zone control! I still shake my head over 2 furnaces.
Boilers are not cheap but as I said before some people and or contractors want to get fancy. You can spend as much on controls as the whole boiler whereas years ago it was one pump and shut off valves ar each radiator which you could adjust for temp. We are to blame for a lot of the high price of building because of what we want not what we need. I would suggest extra thick walls with lots of insulation (foam in places) and small windows. You can't have a house that looks like it belongs in Florida or California and expect not to pay a huge heating penalty.
24C here yesterday!

Roger

[roger g]

Where the edit button Rich. I can't change some poor spelling and grammar.

Roger

[Rich]

Let me look at the permission settings.. I think I have editing turned off - it can get abused somewhat and then posts sometimes will look like they don't really belong together

[roger g]

Thanks Rich. I had to change an "and" to an "as". I seem to find my mistakes after I punch the submit button.

RogerK I was just talking to friend of mine in Bonnyville and he couldn't explain why a lot of houses in Alberta has a furnace upstairs and anotherone downstairs PLUS all the extra ductwork. He just changed a two system into a one system with zone dampers. Two Tstats which operate the furnace and the appropriate damper. The cost of these dampers will curl your toes. Get a price for a furnace with and without zone dampers and the T stats.

Roger

[TinGoat]

I'd definitly go with the radiant floor heating and a single boiler...

You can also opt for a couple of conventional hot water radiators to supliment the system.

I've got the old cast-iron radiators in my 100 year old home and don't find any problems with stale/stuffy air.

When we rewired the house, we made sure that all the ceiling fixtures were wired 14/3 to accomodate Ceiling Fans... Blow air up in winter and down in summer to balance the heating/cooling...

There's no room in the old house for adding duct work without adding nasty bulkheads...

As for zone control... KISS... For radiant floor heating, each room/zone in controlled with a simple shut-off valve. Play with the valves until you are happy with the results and then leave them alone...

Go with lots of insulation. and supliment with electric baseboard heaters or fireplaces...

I wouldn't want to mess with suplimental heating unless you do go with fancy controllers or multiple thermostats... If you warm up the room that has the thermostat in it, then the boiler will shut off and leave the rest of the house cold....

[Dano]

If you can afford the additional up front costs....go Radiant floor....Actually radiant heat does not heat the air or circulate...it heats the objects..consider this...your outside..hot summer day say 90 degree's..under a tree(shade)..you walk out from the shade into the sun and feel instantly hotter...the air temperature is the same but the suns radiant energy has converted it's energy on your body to heat..same as floor heating systems. Forced air systems are actually one of the least efficient systems but cheap up front...remember air is an insulator..therefore your heating an insulator and forcing it throughout. Open a door in mid winter..heat goes to cold and it takes a good amount of time for the system to recover..do the same with radiant system...much faster recovery. Sorry for the long winded lesson.....

[RogerK]

Thanks for the replies, guys!

I am just finalizing the layouts for the house and then bringing them in for quotes for Forced Air, Radiant, and a combination of both (radiant in the slab only). As everything, I guess money is always an object so we want to try to get a good handle on the differential in cost before making a final decision.

Cheers!

Roger.

[MageMinds]

I don't know if you have finished your project, but I would buy a boiler to heat domestic hot water, radiant concrete slab and your ceramic area like bathroom and kitchen (if you plan to put ceramic).

Than with your boiler you only need a Water-to-Air heat exchanger that you then put into an air handler that will circulate air around your house. Send your house plan and localization ta specialist that will calculate your heat load, that way you will sai how much BTU you will need to create to compensate for the heat lost of your house.

The duck work is a good thing since if you want to have central A/C later you only need to by an outside compressor with an evaporator that you only put in your duck, you will need to change your controls, for one that support Heating and A/C.

With that setup you can have a air exchanger with heat recovery easily installed. An other advantage would be the possibility to install a humidifier to your air handler, to regularize your relative humidity in winter or summer if it's dry in your region.

Some stats... Radiant floor heating will cost your 30% less to operate because you will find that you don't need to heat as much as a regular system, when your feet are hot your whole body will feel warmer. Radiant in concrete have a side effect, it's very slow to respond, it could take up to one hour to raise your temperature, I would suggest you to have a floor thermostat (to control the temperature of the floor) and have a thermostat that will control the air handler.

I hope this will help you!

MageMinds