OK,
I justput up a 40X56X12 ft sidewall shop. Now it is time for the heat and
cement work. I had my mind set on radiant floor heat because of it
efficency. But after speaking with my heatin/cooling guy I am thinking twice
about it. He said that it is efficient IF you keep it turned up all the time
and work in it 8 hrs a day. But he also told me the recovery time for it ,
is a long time.
He is telling me to think about it, as I won't be out there everyday. In
houses I guess it is efficient. But he brought up the point of heating it
all the time vs turning on another type of heat for 3 times a week. Then
what do you think is more "efficient" ?
I am just wondering what you guys find as in personal prefences and what you
find "efficient" for the person that will be out in his shop an average of
3-4 times a week ? Or maybe called a classic tinker shop.
I think he is trying to push me into forced air because of the recovery time
and the amount of time I will spend out in it.
What do you think ?
Thanks,
Iowa883
If it was me I'd use a couple of blue-flame propane units that hang on the
wall, and maybe a woodstove. Or maybe both.... The propane to heat the air
quickly and the woodstove for radiant heat in case you're going to be in
there for a long period.
But find out if your insurance will cover you if you have a wood burning
stove. One of the guys at work was all ready to install a woodburner in his
shop. The insturance agent was looking over his shop and said if he
installed a woodburning stove then the company would not cover him. He then
called around and found his premium went through the roof (when he finally
found a company to cover him. This is in the midwest, so it may be different
by you.
Just a thought.....
This is really something you'll have to answer for yourself. Ie:
how cold does it get? How often will you use it? Would several hours
of preheat to working temperatures be a PITA? What temperatures can you
tolerate while working? Do you want T-shirt and shorts working temperatures?
Do the things you're working on/with need to be heated?
Etc.
He's right. Slab heating is _slow_. So, if you expect it to be _warm_,
unless you're willing to keep the thing turned on all the time, or _long_
pre-heat delays, you're not going to be very happy with it.
The best unit for walking in, turning on the heat, and being comfortable
almost instantly is ceiling radiant IR heaters. Especially gas-powered (for
economy of operation).
IR heaters don't warm the air. They warm the solid objects they impinge
upon (especially _you_) up quickly.
They "feel" a little funny - the air can be quite cold, but you're
just fine.
If IR radiant doesn't do the trick for you, forced-air is the best. One
of the most expensive to install, but much cheaper to operate for getting
warm quickly than slab heating.
In my shop, (32x24x8 - much smaller than yours) I have two 4800W 240V
construction fan heaters (often called "cube heaters"). Brings the garage up
30C (from -25C) to useable temperatures in an hour or two, and I can
sustain it with just one heater.
But my idea of "useable" is probably different than yours (I'm happy with 5-10C
working temperatures most of the time). I have a small 1500W electric IR heater
mounted on the ceiling near the workbench to keep _me_ warm for "I need to do
this now!" jobs.
Purchase and installation of my heating equipment was _very_ cheap. Operation
is _quite_ expensive, but, the duty cycle is so low the operational costs
are okay.
In our area, IR radiant is very popular in repair garages, warehouses and
other places that need lots of heat for working, yet have to open their doors
a lot. And restaurants trying to extend their "patio season" ;-)
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
I'd vote for the forced air heat.
You don't say where you are, but if it's a feeezing area,
the on/off of radiant floor can, as I've had it explained to
me, create a lot of stress on the heating parts inside the
cement. I got to watch some of the work at our local SPCA
where they used readiant floor heat. Took it over a day to
get the place up to temp when it was first turned on, but it
was also below zero outside with a wind. Nice, even,
well-enjoyed by the animals heat now though! The kittens
especially love it!
I couldn't get a run to my garage-shop, so I've settled for
using a Reddy heater of 55,000 btu/hr output. Runs on kero,
use about a gallon a day in coldest weather, but best of
all, with the ceiling fan I put in (garage also insulated),
the place heats up on no time. In the worst weather I have
plenty of heat to work in less than half an hour, long
before that danged steel tools warm up! <g>
Fer wat it's woit, 'nyway
Pop
twice
time
you
time
My experience from having a shop ............
Heating is not an issue unless you are in a very cold place. You can wear a
coat until it warms up a bit. You can set the thermostat so that it stays
50 degrees inside, or some low temperature where it won't work a lot when
you are not there, and won't have to work as hard to warm it up from say, 30
degrees. Whatever you do, when the HVAC is running, just picture yourself
throwing $$ bills into a fire. Heating and cooling a shop will co$t.
Cooling is something else. I called the AC guy when mine wouldn't cool the
shop. He said that in order for it to work, I would have to leave it on all
the time. He said it would probably take three days for everything to cool
down in the shop, as I had a lot of metal and metal machinery in there. And
then, when you open the door, whoosh, you gotta start over again.
Heating and cooling a shop is an unique thing in the HVAC trade. Some shops
don't generate a lot of heat. Some do. Some don't have the doors thrown
open very often. Some do.
I would try to heat/cool it for a couple of hours before using it. I would
check out cheap alternatives, like swamp coolers (if they work in your
locale) and wood stoves. Dress for it, too.
HTH, but it is difficult to give you specific advice.
I woud buy a Monitor heater, that burns K-1 fuel oil. It has to be
placed next to an exterior wall, and vents through a tube within a tube
(about 4 inches wide, total). It **draws in** air from the outside,
and vents back out in the tube within a tube. So, there is no
"infiltration" of air.
It is oderless, safe, and very very efficient.
We have a cabin in the mountains, and it gets real cold in the wintertime,
and the Monitor heater is the most efficient source of heat that we could
find, after trying electric central/ baseboard heaters/ wood stoves. It
would heat your shop from a cold temp, in a short time.
The model 2400 has btu rating of 43,000. Here is a link:
http://www.monitorproducts.com/index.html
I have no stock in Monitor heaters, just a happy customer.
--James--
OK Guys,
I forgot to mention my area, I live in South central Iowa , with temps
getting below zero . Also another thing to consider in your recommendation
, is that I live on top of a hill out in rural Iowa .
Does this help on your recommendations ?
Please respond ASAP, As my loan on the shop needs to be wrapped up by
Wednesday .
Thanks so much for the replies,
Iowa883 ( Hence location :-) )
Piece of cake... See
http://users.montanadsl.net/~reysa /
NREL says 930 Btu/ft^2 of solar heat falls on a square foot of south wall
on an average 24.4 F December day in Des Moines. Rotate the shop so one
56'x12' = 672 ft^2 side faces south, if needed, then apply a single layer
of Dynaglas corrugated polycarbonate "solar siding" (which comes in 4'x12'
sheets) over a 6" air gap with vent holes through the south wall to collect
0.9x672x930 = 562K Btu of sun on an average day.
With R20 wall and ceiling insulation and a 2240 ft^2 ceiling and 1632 ft^2
of non-south walls and heat storage under the ceiling, the air coming out
of the upper vents on an average December day might have temp T (F), where
562K = 8h(70-24.4)672/R1+8h(70-24.4)1632/R20+24h(T-24.4)2240/R20, so T1 F.
If the ceiling store has an average (130+80)/2 = 105 F temp over 5 cloudy
days, the shop needs 5(8h(70-24.4)2304/20+24h(105-24.4)2240/20)) = 571K Btu
for 5 cloudy days in a row. This might come from 571K/(130-80) = 11,424
pounds or 178 ft^3 or a 1120ft^2x2" or 2240ft^2x1" of water in overhead
flat plastic film ducts cooling from 130 to 80 F, with a slow ceiling fan
and a thermostat to bring down warm air as required.
Nick
Hi,
The barn collector (referenced above) is still working well. It is
starting to make the garage too warm on sunny warm days, so I plan to
add the outside collector vents, and seal off at least some of the vents
going to the garage soon.
There are some small (but maybe important) things I would change in the
construction. I'll add these to the write up when I get some time, but
briefly:
1) I would add light weight horizontal supports to the glazing at around
2.5 ft intervals -- i.e. two supports for my 8 ft panels. This would
control the tendency of the glazing to bow inward or outward. When the
wind blows from the North, it creates a negative pressure on the South
side of the barn and causes the panels to bow out. This hasn't caused
any failures, but I think over time it might. I plan to add these to
mine sometime during the summer.
I think that something like a 3/4 inch by 3/4 inch would be enough.
Maybe painted white to reflect sun further into the collector?
2) If you can get the 4 ft wide glazing panels this is a real plus, in
that it eliminates the intermediate vertical panel supports, and makes
it easier to add the horz supports mentioned in 1.
3) I would use two layers of black screening for the absorber instead of
one. The one bay I have that has two layers does better.
4) I am about to add the summer vent openings to keep the collecters
from getting too hot during the summer when the vents to garage will be
closed off. I am going to try using a couple of the cover plates that
are used on outdoor electrical outlets. These can just be fliped open
or closed easily, and they have foam gaskets that seal well. I will
install 1 or 2 of these per 4 ft bay in the upper sill, and the same in
the lower sill. I'm not sure if this will provide enough area or not --
I will add the results to the writeup.
-------
I have some thoughts on an even simplier collector for
garage/barn/workshop situations that I'll try to gather together and
post in a few days.
Gary
I missed the original post. My shop is in DeSoto, Iowa (16 mi
west of Des Moines on I-80) and occupies a 2500 ft² aircraft
hanger. I managed to keep the otherwise unheated and somewhat
drafty shop above freezing all winter with the 6'x12' collector
pictured near the bottom of http://www.iedu.com/DeSoto/pix.html -
I plan to rebuild this one and add two more before this next winter.
Stop out for coffee next time you're in the Des Moines area.
Hi,
My climate is similar to yours and we also get wind with the colder weather.
I might qualify my statements with the fact the energy costs in this area
are probably lower than many areas so I lean towards the luxury side of the
issue. Floor heat is luxury. Nothing feels better than when you walk in an
out of the cold and get to walk onto a warm floor. You are going to get
some thermal lag even with forced air heating, especially if you have a 6
inch floor. It is darn near impossible get warm and feel comfortable until
the floor is warm. A thick slab of concrete tends to stabilize temperature
so your ability to adjust temps quickly will be limited either way.
I have both floor heat and the fan type heaters that hang from the ceiling
and are thermostatically controlled. That gives me a lot of flexibility.
One nice thing about the floor heat is the heat starts at the floor and of
course drifts upward, while my blowers blow it at the floor and I assume
very quickly its back on the ceiling. Next, two doors are open at opposite
ends of the building are open and the wind carries all the heat away. I
doubt that it has any scientific justification but it seems that the floor
heat is a bit more immune to loss.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.