Types of Heaters
Generally, space heaters with fans are the most difficult here are some other options organized by type.
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1. Heat Dishes/Infared Heaters
Optimus dish heater is one I have used before. Others very sensitive have found that this type of heater has very little to offgas and does not take a long time.
It does burn things if it is too close to objects and that is a risk.
There are a number of brands selling similar dish-style heaters on Amazon.
One super sensitive person did well with this tripod infrared heater.
2. Ceramic Heaters
For the extremely sensitive, universal reactor, the Ceramiciruit portable space heater is the way to go.
This is the most tolerated that I have seen, and I have not seen anyone not tolerate it yet.
But it is very costly at $988 plus shipping (approx $50 to ship to many parts of the US). If you are not a universal reactor I would try some of the other options from Amazon first.
Update: In Winter 2020/21 this is no longer listed on their website.
Another type of ceramic heater is the one pictured above. This is a wall panel that is quiet and low profile. I tried that one and it did have an odor at first (I had to put it outside for 24-48 hours). I found it fine after that amount of time.
It’s not as good for the chemically sensitive as the Ceramicircuit above but I like this style a lot.
Keep in mind it’s only 400 watts, so you need three of them to make up one regular space heater.
3. Cadet Portable Baseboard Heater
Another great option for the highly sensitive. Baseboard heaters are normally wired in but this one plugs into a regular outlet.
It’s 1500 watts.
4. Quartz Heaters
The next best-tolerated type is quartz heaters. Some sensitive folks have recommended the Optimus tower quartz heater.
There are other types of quartz heaters, but simpler is better. Optimus also makes a lower-profile version that others have liked.
While space heaters with fans are not always the top choice, I have used some successfully with a few days of offgassing. Other sensitive folks have found this Vornado series (VMH10 to VMH600) to be very good.
5. Convection Heaters
The Patten Utility Heater was tolerated by someone who could not tolerate other convection heaters after some offgassing.
It has been reported as noisier than others. There are a number of metal housing utility heaters. Some report only needing a couple or a few days to offgas them.
Dyson, heater/fan/HEPA filter is also well tolerated by some.
6. Radiator Heaters
Oil-filled radiator heaters are used by many EI folks. The oil is well sealed and should never leak out. I have seen it happen once but that is a major defect and failure.
They look inert but they do offgas through the small vents in the front piece. Depending on your level of sensitivity I would say these heaters need to be offgassed for a while.
Not having the noise of a fan is a plus for most people. You can find inexpensive versions. If you plan to run this and offgas it for a while, I would get a good quality one so that it will last you a long time.
7. Glass Heater
This heater is two pieces of glass with a 500-watt heating element in the middle. I have not seen it myself but I would expect it to have no to very little offgassing since glass is a perfect block of VOCs.
Emergency Heat Options
Heating blankets (can take a very long time to offgas), biomats (a little more tolerable) – those two won’t work for the most sensitive.
Mold and HT-sensitive folks have liked the Biddenford brand of electric blankets the best.
But the most tolerated hot water bottle is the Japanese Yutanpo metal water bottles. The least toxic plastic hot water bottles are the Fashy thermoplastic line.
Other Heating Options for the Chemically and Mold Sensitive
The first type, the kind that is not safe for sensitive folks, in my opinion, is a portable propane heater like the Mr. Heater Buddy Heater.
They use air from inside your living space to burn, then vent the combustion gases inside your living space.
These are designed to be used outside or in a garage or space with lots of ventilation. They are not really intended for indoor spaces.
The second type called “B vent” or Natural Vent uses some air from inside your living space, but vents the combustion gases outside. This is similar to a gas fireplace. They’re usually used in residential houses or mobile homes which are large enough to have oxygen to spare and ample make up air.
Direct Vent Heater
A direct vent heater has an exhaust and an intake. The device is a sealed system, using no room air for combustion. Exhaust fumes vent out of a side wall or roof.
This type is safest (and most efficient) for small or tightly sealed spaces.
It takes air from outside and uses it for combustion, while also bringing in air from inside and heating it in a sealed heat exchanger before sending it back inside.
Indoor air is never used for combustion and it’s physically impossible for the combustion gases to get inside. Technically all combustion takes place outside of the building envelope.
Ductless Mini Split Heat Pump
This unit does not exchange inside and outside air. There is not much offgassing compared to other heating and cooling units.
Carl Grimes suggests if new AC equipment like heat pumps have an offgassing odor then that could be from heavy oil on stamped metal parts.
It can be removed with a petroleum solvent, rinsed with hot water plus a non-toxic detergent, then water only.
Keeping a mini-split heat pump mold-free:
There is some debate on whether a mini-split can be kept clear of mold. I find these units easier to keep mold-free than any other type of AC.
The unit should come with a fine mesh filter on the front, once you take off the front panel you can access the coils. Keep that filter clean. Clean this filter once a week.
I never got dust and mold on the coils in my mini-split. If your coils start to get dirt, grime, or mold, clean them. Make sure your unit is easily accessible.
You spray the coils down with water and cleaning products. Companies can come and do this part for you since it’s a little tricky.
You can also do this as a preventative cleaning.
MIAQ says to do this every two years as you might not see the mold unless you open this up and take a flashlight to it. You can do this every year if you are sensitive to mold.
If you are there for the installation, make sure the condensation tube is not too small. It should have a straightforward route out and where it empties should be easily accessible for you.
You can pour hydrogen peroxide down the tube to clean it or you can also blow it out with pressure or suction it out.
Don’t wait until it’s plugged and overflowing to clean it. If that becomes moldy it may be impossible to perfectly clean so preemptively cleaning it is a good idea.
You could ozone the unit a couple of times without damaging it.
Corinne Segura is a Building Biologist Practitioner with 7 years of experience helping others create healthy homes.
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