Workshop Climate Control: Insulating, Heating and Cooling Your Woodshop

Too hot in your shop for woodworking? Is the winter freeze keeping your glue from setting? Welcome to the article that sets you on the path towards the perfect woodshop climate! You can blame the woodworkers over at the Wood Whisperer’s new “Town Square” for inspiring me with their thread: Shop Heating and Cooling

Here’s what you’ll find below:

1) Insulating Your Woodshop
2) Heating Your Woodshop
3) Cooling Your Woodshop
4) Humidity Control in Your Woodshop
5) More Air Quality Resources

1) Insulating Your Woodshop
Your first and foremost consideration for heating or cooling your woodshop should be INSULATION. I’m going to make this point first with an opinion from Woodnet’s RokJok (in Shop heating: Insulate, insulate, insulate!):

“How you heat the shop is less important than how well your building retains that heat.”

Here’s a quote from “Winter Woodworking: Thoughts on Heating the Garage Shop” by Howard Ruttan that helped me get the importance of insulation: “Heating a shop is a lot like filling a goldfish bowl. If you drilled several holes in the bowl, the water would continue to leak out until what’s in the bowl is the same as what’s outside of it. Unless you want a dry bowl you have to keep pouring in the water until your water bill goes through the roof.”

And now back to RokJok of Woodnet. Here’s his heating bill after spending $1500 on insulating his shop:

BEFORE: 12/21/07 – 1/22/08
Number of days: 32
KWH used: 6053
Avg KWH used per day: 189.2
Total charge: $576
Cost per day: $18.00
Avg temp: 38 degrees F

AFTER: 2/21/08 – 3/21/08
Number of days: 29
KWH used: 1281
Avg KWH used per day: 44.2
Total charge: $118
Cost per day: $4.07
Avg temp: 44 degrees F

Total savings for month: $458
Savings per day: $13.93

I read repeatedly folks saying that you should insulate your ceiling AT THE VERY LEAST. Even if you do nothing else you’ll still see a decrease in your heating costs. If you’re unable/unwilling to insulate and still want more heat then read Heating an uninsulated workshop in Woodnet where most folks suggest a radiant heater of some sort.

One note – for anyone insulating who doesn’t currently use dust collection and respiration for lung protection… Insulation’s going to close off all the little cracks that used to provide some small level of ventilation. If you insulate you’re going to REALLY have to start paying attention to dust collection and respiration.

General Insulation Advice/How-To’s:
Department of Energy’s Insulation Fact Sheet
How Not to Insulate Your Attic from Mother Jones
Air Sealing the Home Garage

Insulation Discussion From the Forums:
Shop heating: Insulate, insulate, insulate!
Heating an uninsulated workshop
Foam Insulation

2) Heating Your Woodshop
Far more woodworkers want to HEAT their woodshops than cool them, judging from the number of forum threads. Igniting dust will ALWAYS be a huge concern when it comes to heating. That’s why most folks recommend either radiant hot water heating or direct vent heaters with sealed combustion. You gotta keep those open flames out of the workshop! Sawdust plays a non-flammable role with forced air heaters. You’ll be changing or cleaning lots of filters, even with a good dust collection system.

I found this description which seems at first glance like a “holy grail” of woodshop heating from woodweb:
“If you’re going to build a shop from scratch with a concrete floor, I would wholeheartedly endorse using radiant heat with an outdoor wood boiler. You affix Pex flexible plastic tubing to your remesh grid in an “S” pattern to cover the area and then circulate hot water from the boiler to heat the shop. If it’s a big area, you’ll want to use two loops, overlapping – one which starts at one end with a hot water inlet and the overlapping loop which is reversed. This prevents one end of the slab from being considerably warmer than the other. You have to insulate the slab and use a thick plastic vapor barrier (6 mil or better), but the end result is a toasty shop with no indoor moving parts or exposed heat exchangers to worry about getting clogged with sawdust. Another plus is that you can have all the hot water you can stand for next to nothing. And it provides a great means of disposing of your wood scraps. If you’re building a shop from the ground up, this is the system to consider.”

The one problem I can see with the idea is that you won’t be able to maintain minimum temperatures during the night without continuing to feed the wood stove outside. Also, come to think of it wouldn’t it take awhile to thaw and reheat the water?

I think your best bet – if you’re starting from scratch – is an electric thermostat-based radiant heater to keep your shop at a minimum temperature. This minimum temperature is crucial for glue ups and finishes. Then add some small, quick heating mobile units for when you’re working.

Here are some types of heaters I found discussed repeatedly (no brands):

Radiant infloor heating (hydronic heating)
direct-vent natural gas wall furnace
Solar Heating
Pellet Stove (burning your sawdust…)
forced air electric heater on the ceiling
electric radiant heaters (no fan)
electric baseboard heaters
a wood stove (no thermostat + bad for glue ups and finishes)
window unit combination heat pump/heater and Air Conditioner

One More Insulation Nag…
I can’t emphasize enough the importance that insulation will play in keeping that heated air where you want it. AT LEAST insulate your roof and seal all the noticeable drafts.

Heating Articles/Discussions from the Forums:
Heating and Cooling Workshop
Heating a Woodshop
Woodshop Heating Options
Winter Woodworking: Thoughts on Heating the Garage Shop
I need heating advice for a basement woodshop
Heating a small shop with gas
Shop Heating Economy
Fall is here. Time to think about how to heat the shop this winter
New shop needs heating
Cool Options for Workshop Heating

3) Cooling Your Woodshop
There were fewer folks discussing methods for cooling woodshops though there was greater passion… Especially in places like Arizona… Some of the same general concepts apply as in heating your woodshop. Insulation, obviously, is key. The increased dust will necessitate more frequent filter changes on window units. Because there were fewer solutions I decided to list out all those I found, along with links that discuss them.

Possible Solutions for Cooling Your Wood Shop:
Run ducts from the house
an Evaporative cooler
Mini-Split/Ductless Air Conditioners
Roof extractor fans

Discussions about Cooling Woodshops:
Cooling A Garage Shop
Arizona A/C Recommendation
Need advice on HVAC for detached garage/workshop
A/C on the wood shop

4) Humidity Control in Your Woodshop
Swelling joints. Cracking, shrinking lumber. Rust. Humidity can really put a wood shop to the test. The main concerns when it comes to climate control is putting water in the air or taking it out. Here are some resources that should help get you started

Dealing with Woodshop Humidity (from Rockler)
Industrial Air Quality
Dehumidifiers Buying Guide
Humidifiers Buying Guide

5) More Air Quality Resources:
5 Top Air Respirators for Woodworking
Cyclone Dust Collectors: Gorilla vs. Clear Vue vs. Grizzly