RV Heat

RV heat that magical thing that can turn a cold night into a toasty warm experience and make the great outdoors seem a lot more tame. When I wrote about cold weather camping I wanted to include more information on furnaces but it was quickly getting off topic. So I decided that I would write just about RV heat. There is a lot of misinformation about RV furnaces so I want to dispelled some of the myths.


Before I get started I want to address something that is always brought up when talking about heating an RV. Smoke detectors, propane detectors and carbon monoxide (C0) detectors. I strongly believe even in a non heated RV that you should have all these detectors (propane if you have propane for cooking). In a heated RV you should not spend one night in the RV without them. Most ways of heating are perfectly safe but why risk it. A good set of detectors will set you back $100 – $150, not a lot of money when your life is on the line. I also believe that you should have a smoke and C0 detector at home but that is for another post.

RV Heat Sources

Most RV’s come with a furnace of some type. The only type of RV that you may find coming without a furnace is a tent trailer. But as tent trailers get more elaborate furnaces are becoming a lot more popular in them as well.

The biggest issue that RV furnaces have is that the manufacturers seem to think they are there for looks only. They locate them in bad spots with no air flow. They put the thermostats too close to the furnace and many do not use ducting to spread the heat around. Also instead of going one step further and running ducts into basements and storage compartments they don’t. Now it is easy to understand why. It comes down to cost AND how much someone will use the RV in cold weather. BUT honestly the cost would be minimal during the build and could easily be offered as an upgrade option like a winter package.

Forced Air Propane Furnace

So how are RV’s heated? Most RV’s built in the past 10 years in north America have a propane forced air furnace. These operate just like a forced air furnace at home in that the fuel (propane for the RV) is brought into a combustion chamber where it is burnt. The heat from the burn is used to heat a heat exchanger. The burnt fuel (exhaust) is then expelled outside of the furnace and RV as exhaust. At the same time cooler air is drawn from the inside of the RV through the heat exhanger and heated. That air is then returned to the RV nice and hot.

A point to note here is that the combustion air & exhaust ARE NEVER MIXED with the inside air! If the furnace is operating properly this process is 100% safe both in a house and in an RV. IN some RV’s the furnace also uses ducting to distribute the heat around the RV. Some even heat the storage compartments or tank areas.

Gravity Propane Furnace

Older RV’s may have a gravity furnace. These work the same as a forced air in how they heat the heat exchanger. But they rely on air to warm and rise to get the air circulated over the heat exchanger not a furnace to move the inside air. Not as efficient as a forced air furnace in heating. They use a lot less power as they do not use a fan. Many people that camp without power hook-ups love gravity furnaces. They do not need to worry about a huge power draw. Just as safe as a forced air furnace.

Gas or Diesel Heaters

White Turtle III Espar

The other popular way of heating an RV is using a heater that uses diesel or automotive gas instead of propane as the fuel source. They operate the same way as the propane furnace with the exception of the different fuel source. These come to us from Europe where they are a lot more popular than North America. They are also used in semi trucks a lot more than in RV’s. They are as safe as the propane forced air systems and they use a motor to blow the internal air. Some people prefer these as there is one less fuel source to carry in the RV.

Furnace Thermostat

Like at home you will have a thermostat that will tell the furnace (forced or gravity) when it needs to fire up. Then it will run till the thermostat is up to the set temperature.

There is a huge difference in thermostats. Some will keep the heat within a degree or two of the set point. Some vary up to 10 degrees from the upper limit to the lower limit of what you set the temperature to. If you find your RV is getting really cool before the furnace cuts in then gets really hot before it cuts out this is a thermostat issue not a furnace issue. Get a thermostat that has less variation to stay more comfortable if this is an issue.

Non vented Catalytic or Combustion Heaters

This will annoy a lot of people that I am lumping them together but there is a reason for that. They both operate inside the RV without a vent. I treat both the same even though there is a difference. I believe personally that the difference is slight. These heaters operate by burning propane inside the RV and expelling the exhaust into the RV interior air. Some argue one is safer than the other but I believe that they both need to be treated with a lot of respect. But not with fear.

If you are using either one you NEED to open a window or two for fresh air. ALSO YOU NEED to have a full set of detectors to keep yourself safe. These heaters work really well as all the heat is used in the RV as heat, you do not loose any heat in the exhaust. Some have a thermostat but most have a dial that says low, medium or high. I would not sleep with either one running but I know people that do. I have one I use for heat in extreme cold or for a back-up heat source in an emergency. The other great thing is that they are portable. Ice fishing, hunting or working outside in the cold and you can bring it along

RV heat backup

Vented Catalytic Heater

A vented catalytic heater is a catalytic heater with a vent to the outside to expel the C0 and the propane moisture. If I was using my class C more in the winter this is the route that I would go for heating. Hardly any power draw and as safe as a furnace. The best of both worlds. You do need to have a supply of combustion air available so the fan can draw air through the heater but it is easy to do with one window open the slightest.

Wood Stove

There are a number of tiny wood stoves for boats that are available. I know a few people that use them and they say they are amazing. If I had the space in any of my RV’s I would put one in as much for the look as the free heat. They use outside combustion air and are completely safe. They put out a lot of heat for just little fires. I know of a couple people that live in their RV’s year round and in the winter say it is easily plus 20C with even the smallest fire.

Electric Heat

This is one of my favorite heat sources but you do need to have a plugin. First it is a lot quieter than a propane furnace. Secondly it does not burn propane or gas so can prolong a trip. I have a nice stand-up electric heater with a built in thermostat that I use at my studio in the front entrance and when I head out on trips I take it along. It puts out a lot of heat and the nice thing is that I can put it where I want the heat. If it is not really cold at night I put it between the passenger and drivers seat. If it is really cold I block off the front of the RV and put the electric heater further to the rear.

Moisture in the air

I hear a lot of misinformation about moisture in the air in an RV. This information is made up!!! People take some facts and twist it to fit their idea. Then they take every opportunity to post about it even quoting others that are as wrong as they are.

Propane Stove
Four burners and an oven will add to your moisture when all cranked on making supper


Propane contains water – Fact. When you burn propane water is emitted – Fact. If you use a oven, stove top or an unvented catalytic or combustion heater you will add water to the inside of your RV as they are not vented – Fact.

Forced air & gravity furnaces, gas & diesel heaters as well as wood stoves DO NOT add moisture to the air. They are a dry heat source. They take whatever the air is inside and they heat it, that is all.

The big issue in cold weather is with snow & wet gear. The inside of an RV gets damp when we bring wet things in. We also notice moisture more in the cold as windows and doors get frosty. Then add to that cooking (stove top or oven) exhaust. Plus the moisture from the food. Plus the vapor that we breath out. The inside of the RV is more like a sauna then anything.

So people then say they get moisture from their heaters – WRONG! Forced air & gravity furnaces as well as gas & diesel heaters CANNOT AND DO NOT add moisture!!! If they are / do you have a huge problem as the exhaust is not working correctly!!!!! You are at risk of C0 poisoning if this happens!! Furnaces burn fuel in a combustion chamber and the moisture is outside the RV at all times unless there is a leak.

Controlling moisture

I strongly recommend airing out your RV daily to dry it out in cool or cold weather. It makes life a lot nicer when you do not have a pile of moisture freezing to the walls.

Also if you can dry your gear at a laundry-mat as often as feasible.

For more information look at my cold weather camping pages.