I'm in the process of getting quotes for hydronic radiant floor heating to
be added to my 1st floor of my 100 yr. old house. I live in NH and the
winters are cold and the woeful baseboards can not keep up.
I'm thinking heated floors would be a great addition for
comfort/convenience/efficiency/resale value.

My basement has full access and is cement floored. The floor joists are
accessible but are not all on 16" centers. The centers range from 13" to
22"! Damn old home builders! Makes insulating a little more difficult but
I'll manage. All of the exterior walls have blown-in insulation and all of
the windows are double hung, thermopane windows.

My oil-boiler is less than 20 years old and seems to be working fine (87%
efficiency according to last tune up).

Has anyone done this and regretted it? I'm sure it's expensive (probably
between $5k and $10k) but I'm really wanting to try this.

I would put up Reflectix insulation to reflect the heat back into the floor.
The latest technique seems to be hang the PEX tubing about 1" under the
subfloor, attached to the joists. Then insulate the hell out of it (R19) to
heat up the "pocket" of air between the joists and push it into the floor.

Then you set the thermostat to one temperature (68 or so) and leave it.
None of the turn-down-at-night-turn-up-in-morning scenario. Set it and
forget it.

I've been in a couple houses with this and I was instantly hooked! Warm
furniture, warm feet, generally a comfortable and cozy feeling.

With winter in New England last about 6 months (!) I figure I need to
upgrade to help be comfortable for half my life.

Thoughts/tips/tricks/caveats?

Thanks.

GB wrote:
I'm in the process of getting quotes for hydronic radiant floor heating to
be added to my 1st floor of my 100 yr. old house. I live in NH and the
winters are cold and the woeful baseboards can not keep up.
I'm thinking heated floors would be a great addition for
comfort/convenience/efficiency/resale value.

My basement has full access and is cement floored. The floor joists are
accessible but are not all on 16" centers. The centers range from 13" to
22"! Damn old home builders! Makes insulating a little more difficult but
I'll manage. All of the exterior walls have blown-in insulation and all of
the windows are double hung, thermopane windows.

My oil-boiler is less than 20 years old and seems to be working fine (87%
efficiency according to last tune up).

Has anyone done this and regretted it? I'm sure it's expensive (probably
between $5k and $10k) but I'm really wanting to try this.

I would put up Reflectix insulation to reflect the heat back into the floor.
The latest technique seems to be hang the PEX tubing about 1" under the
subfloor, attached to the joists. Then insulate the hell out of it (R19) to
heat up the "pocket" of air between the joists and push it into the floor.

Then you set the thermostat to one temperature (68 or so) and leave it.
None of the turn-down-at-night-turn-up-in-morning scenario. Set it and
forget it.

I've been in a couple houses with this and I was instantly hooked! Warm
furniture, warm feet, generally a comfortable and cozy feeling.

With winter in New England last about 6 months (!) I figure I need to
upgrade to help be comfortable for half my life.

Thoughts/tips/tricks/caveats?

Thanks.




You will want to nail heat spreaders[ aluminum thingies] to the floor
and then pop the tube into them. I would not think you would want
suspended tube, very inefficient. If you are running it as a secondary
system, you really need to put a primary secondary system to lower the
water temp to the floor. Insulation below is of course a must.

go to heatinghelp.com 'the wall' and there are a lot of pros there who
know quite a bit.

If your house is well insulated, it shouldn't take much to heat it, so I
might look at what is going on there as well, not that radiant isn't great.

"GB" wrote in message
news:1135009577.177722@sj-nntpcache-3...
I'm in the process of getting quotes for hydronic radiant floor heating to
be added to my 1st floor of my 100 yr. old house. I live in NH and the
winters are cold and the woeful baseboards can not keep up.
I'm thinking heated floors would be a great addition for
comfort/convenience/efficiency/resale value.


Why does the baseboard not keep up? If the boiler is not putting out
sufficient heat, the radiant heat will be no better. It takes a certain
amount of Btu's to heat the house no matter what type of system you use.

Is the radiant heat going to run off the same boiler or an additional one?
If the same, thee are water temperature considerations. Before you spend a
lot of money, be sure you have the figures as to how much heat you need and
be sure you have the ability to generate it.

"Edwin Pawlowski" wrote in message
news:LEBpf.299$dh2.293@trndny08...

"GB" wrote in message
news:1135009577.177722@sj-nntpcache-3...
I'm in the process of getting quotes for hydronic radiant floor heating
to be added to my 1st floor of my 100 yr. old house. I live in NH and
the winters are cold and the woeful baseboards can not keep up.
I'm thinking heated floors would be a great addition for
comfort/convenience/efficiency/resale value.


Why does the baseboard not keep up? If the boiler is not putting out
sufficient heat, the radiant heat will be no better. It takes a certain
amount of Btu's to heat the house no matter what type of system you use.

Is the radiant heat going to run off the same boiler or an additional one?
If the same, thee are water temperature considerations. Before you spend a
lot of money, be sure you have the figures as to how much heat you need
and be sure you have the ability to generate it.


The baseboard is woefully under spec'd for the home.
Original house has huge cast iron radiators.
Previous owner decided to add baseboard by himself.
He ripped out all the rads and mickey-moused a baseboard setup.

HVAC company came in and did a calculated heat load for my house and my
system.
There should be X amount of feet in each room and I'm anywhere from 5-12
feet short of baseboard in various rooms.
The runs is not in a "loop" but each baseboard is tapped off the supply line
and returned to the supply line with tees.
Also...the baseboard supply lines are 1/2" from the boiler.

HVAC company wants to pull it all out, replace with 3/4" feeds and add
baseboards in a bunch of rooms.
He quoted around $2600 for this work.
An additional quote was near that so I'm not too keen on that since the
contractor said "That might do it".

If I'm going to pay that much, I'm gonna go the whole boat to a radiant
heating system.
More energy efficient, nicer heat, warm floors, etc....
High initial cost but that's OK. I can suck it up. I'm sure the benefits
will be worth it in the end.

I've been in a couple of homes that have this retrofit and both had the
tubes suspended in the joist bay, not stapled directly to the subfloor.
Apparently, if you insulate well, it's not that much more inefficient than
the aluminum plates stapled to the subfloor.
I've heard from many that this methods is noisy as the plates
expand/contract.
If you ever add hardwood flooring, nails can penetrate the PEX tubing during
install.
Hanging them 1" down the joist helps alleviate this possible problem.

Plus, when I remodel a couple of the rooms next year,
baseboards won't be in the way of new drywall/plaster and furniture can be
pushed up against the wall...along with TVs and stereo equipment.

I've been in a couple of homes that have this retrofit and both had the
tubes suspended in the joist bay, not stapled directly to the subfloor.
Apparently, if you insulate well, it's not that much more inefficient than
the aluminum plates stapled to the subfloor.

I think it is significantly worse, but I could be wrong

I've heard from many that this methods is noisy as the plates
expand/contract.

glue is the answer. The pex expands in the alum, but if it is rtv or
urethaned in, it can't
If you ever add hardwood flooring, nails can penetrate the PEX tubing during
install.
Hanging them 1" down the joist helps alleviate this possible problem.


If they are in plates, you know where they are. My above the subfloor
system had no punctures.....til this year, under the floor where it
exited, caught it before sheetrock went up, so same could happen in any
system. If you ever add hardwood[is this really oging to happen?], you
trace the[ perfectly straight] path of the tube in plates, and avoid
them, usually running at a right angle to the tube helps.

An oil boiler 20 yrs old, 87%, how did they test it, because I dought
it.

"m Ransley" wrote in message
...
An oil boiler 20 yrs old, 87%, how did they test it, because I dought
it.


It's on the spec sheet after they clean and service it.
87%.
I thought that meant efficiency but maybe it means something else.

"GB" wrote in message
It's on the spec sheet after they clean and service it.
87%.
I thought that meant efficiency but maybe it means something else.

I have the same thing and yes, efficiency. . Reads 87.5% one year, 88%
another year, after cleaning. My heater is 28 years old.

Edwin Pawlowski wrote:
"GB" wrote in message

It's on the spec sheet after they clean and service it.
87%.
I thought that meant efficiency but maybe it means something else.


I have the same thing and yes, efficiency. . Reads 87.5% one year, 88%
another year, after cleaning. My heater is 28 years old.


That is a gross efficiency number, really a blind friggin guess, not an afue

They mean burner efficiency, not boiler efficiency. Testing a burner is
fairly easy , testing efficiency of a boiler gets into alot of
parameters and time. It is likely an 77-80 % unit overall at that age.
You can have an 87% efficient flame and a 60% efficent boiler design
,for example. Non condensing wont be over apx 83%.

I wonder if you need to insulate that much. Still air is R5 per inch
for
downward heat flow so it would seem a radiant barrier would be enough,
maybe
with a small R-value since it won't be 100% reflective and will get
warm.
I was planning to try this with 1" polyisocyanurate board across the
bottom
of the joists and nothing in the joist bay except the pex.

There is also 'local wisdom' here that heat spreaders can be replaced
by
higher water temperature. It would seem that hot spots would be the
only
downside and your idea of hanging the pex would reduce that as the air
at
the top of the joist bay above the pex would get heated convectively,
whereas
the air beloww the pex would be stagnant and thus R5/inch.

HTH