Mobile home oil tank (C) Daniel FriedmanManufactured / Mobile Home Heating Repair FAQs
Q&A on Heating/Cooling Mobile Homes, Double wides, Trailers

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Mobile home heating system diagnosis & repair questions & answerss:

FAQs help troubleshoot problems in the heating systems in mobile homes, trailers, double-wides, multi-wides incuding furnaces and boilers, inadequate heat distribution, freeze-ups, and safety hazards also manufactured home heating ductwork defects.

Page top sketch was provided courtesy of Carson Dunlop Associates, a Toronto engineering, education, and home inspection company.

Green links show where you are. © Copyright 2017, All Rights Reserved.

Manufactured Home & Mobile Home Heating System Repair Questions & Answers

Mobile home oil tank (C) Daniel Friedman

Questions & answers about manufactured home heating systems or mobile home heating systems posted originally at MOBILE HOME HEATING

On 2017-10-26 by (mod) - I can see the ground through the heating register in my mobile home


That suggests that your heating or cooling ductwork has fallen away from beneath the home. You or someone who can help you should take a look below the home.

If you can send me a photo of the vent and surrounding floor and then of a the view through the vent that would perhaps help me make other suggestions.

If you can, have an inspector look over the home for you. The cost will usually more than pay for itself by reducing the chances of a very expensive surprise.

I don't know a thing about the home you're looking at, but as an old guy who has inspected many buildings, when I see even one clear example of evidence that someone maintaining the home had no idea what they were doing, that puts me on alert to see what else they did.

On 2017-10-26 by Jackie

Why would I be able to see the ground through the heater vent on the floor of a mobile home?

On 2017-09-10 by John

We live in a older trailer it's got a fence . what's heat go on .

On 2017-04-05 by (mod) -


I suggest measuring the actual dimensions of the opening into which the metal frame fits, using that to define the physically biggest new unit you can buy that fits in the original wall opening.

Usually you can buy a physically smaller unit if it's BTU capacity is enough, then you'll need to block the remaining opening and seal it against wind and rain.

It may be more difficult to find a new air conditioner that fits exactly in the old sleeve. I'm reluctant to insist on that fit.

On 2017-04-05 by Anonymous

My through the wall Air conditioner stopped working. I need a new air conditioner to replace the old one. I live in a mobile home the old unit is in the wall so you don't need to cut a hole i just need a new air conditioner to be installed securely in the wall. It already has a metal frame to hold air conditioner. Its not very big maybe 1H X 2W X 2D

On 2016-12-31 by (mod) -

Look for a leaky, crimped, or improperly-routed heating duct - if it's a forced warm air system.

On 2016-12-31 by Julie

Forgot to mention its a modular

We live in a large 4 bed 2 full bath ....why is one of the bedrooms at the end of the house freezing

On 2016-12-27 by (mod) -


If you mean that the trailer electrical system shuts down when you are running the heat, that sounds UNSAFE to me - as if there is an electrical problem.

Are you using electric heat?

I would not run equipment that seems unsafe - instead you need to call a repair person. If your heat is electric, an electrician is the person you need.

Keep me posted.


On 2016-12-27 by rita

When we tirn on heater it shuts the whole trailer down in 10 min

On 2016-12-20 by Gray hays

Got cold blowing when I need heat the people cone out and switch something to fix,what they switch??

On 2016-12-09 by (mod) -

Actually the best thermostat location is probably in the coldest room and in a spot where it's not thrown-off by sunlight, hot air or cold air blowing on it or some similar snafu.


On 2016-12-09 by Sherry

I recently bought a doublewide. Its always cold in here. I keep the thermostat on 72,.. which sounds high,.. but its still cold! & I have bumped it up to 76-78,... & still feel a chill in here! Doesn't it matter that the thermostat is in a separate room from the air return?!

Based on my years cleaning new construction,.. I know they are supposed to be close! Help,... I don't want a $400 electric bill & I know that's what I have by keeping it set at 72+!!

On 2016-12-09 by (mod) -

John it seems to me there's either a blockage, leak, or a duct run that's too long or wrong size. An experienced heating guy ought to be able to spot those problems. Keep me posted.

On 2016-11-30 by john d

I have a 1993 Double wide Furnace I get great air flow on front side. On the back side is where the furnace is I get great air flow on room north of furnace. South of the furnace the flow is less than half. I have had it looked at All the duckwork is clear.The service man can not find any problem. What is my next step.

On 2016-11-20 by Jason

We live In a dbl wide mobile home in florida. we almost never use the heat, however it got a litrle chilly the other night. We turned the heat on to take the chill out, as we have done in yrs past, but only cool air came out of all the vents.

We didn't even smell the usual "whats burning" smell that we normally smell when turning it on for the first time of the year. It has been about a year since the heat was last turned on. Could this be a diy fix, or do we need to call someone? We left the heat on for at least 30 min by the way & still cold air.

On 2016-11-12 by kat

we are having an incredible amount of dust. is it the return air?

On 2016-10-09 by Mike

I have a 1968 Paramount doublewide trailer. In the small bedroom there is a vent 10.25in x 20.5in. Can you tell me what this vent is for? There is insulation in the bottom of this floor vent between the wood joist. The a/c and heater were replaced prior to my purchase.

There is a return for the hvac system in the hallway. I am replacing the carpet and would like to know if this needs to remain open with the vent cover or if I can seal it off. I have no idea what it is for and have no floor plan of this trailer. The previous owner recently past away, so I also have no one to ask.

On 2016-07-06 7 by (mod) - A/C system that's not cooling properly

Niki, I appreciate the frustration of having an A/C system that's not cooling properly, but we can't reliably diagnose the actual problem at your DW home by an e-text.

Problems range from crimped/disconnected/leaky (easy to fix) to under-designed or poorly-located supply and return registers or even an improperly-sized air handler. You want to understand the specifics of what defects your AC guy finds - and to see them. That will make it easier to agree or not with any repair proposal.

On 2016-07-05 by Niki

I have a 1980 approximately 1500 sq. ft. DW that has a/c and heating ducts running from the ceiling and the floor registers are used as the return which lead to the air handler outside in the storage room with the filter being underneath It.

The system seemed to work well with a 4 ton 9 SEER York although you only truly felt the 2 floor registers nearest the air handler having strong suction and I believe the other rooms have 2" x 4" boxes underneath the floor registers and I don't know if they are all connected or not.

Problem is that now we upgraded to a York unit, 3.5 ton, 15 SEER, 410 freon system ( not sure what size air handler is in but we were told it matches) and we can not get the system to work properly.

My a/c guy thinks the return is poorly done and claims that is the problem. We have more pressure blowing from the above air vents on either end of the house but not much in the centre. I live in Phoenix, AZ and in the afternoons we ca not get the temp to go below 80 to 81 degrees and it runs constantly.

I am reading that the evaporate coils might need to be bigger, the lines may be too small and other factors could be the cause other than the returns that are in the floor. Most rooms do have 2 vents in the floor, the living room has 3, and it seems adequate although u only feel those 2 registers nearest the air handler having suction.

They found a big piece of insulation in one of them and we don't know if they are all connected or not. This is unacceptable for having a brand new system just installed.

Right now in the heat of the day it feels like it is blowing maybe 12 degrees lower than what the house temp is and that should be around 20. This is unacceptable. My a/c guy isn't giving up but now he wants to put in a new 16" return up on the ceiling.

He is coming by to show me what he intends to do and it of course will have to cost me some money. Is this the problem? I explained this pretty well and am hoping you might know if this is the proper solution or not.

Any other suggestions? I am about to call other hvac installers for estimates on correcting the problem. What do I want to hear to know who's going to get it right?

On 2016-05-30 by (mod) -


If the A/C is weak at some registers I suspect the ductwork is disconnected, torn and leaky, or blocked, or your air handler for your A/C system has a very dirty filter that needs to be changed. If you search InspectApedia for "WEAK AIR FLOW" you'll see more on how to diagnose the problem.

If the air that is supplied comes out warm then your air conditioner is not working - could be out of refrigerant, or could be the outside compressor/condenser is not even running.

On 2016-05-28 by Doris

I have a trailor I'm ting to use my central air it cones out in the living room and kitchen slow but the beds rooms and bathroom it cones out warm why is that

On 2016-05-14 by (mod) -

Cathy DO NOT block air flow to your heating appliance or you may cause it to produce fatal carbon monoxide due to lack of adequate combustion air.

You should not to kill power to an A/C system in winter nor a heating system in summer if you set your thermostats properly. It's ok to kill power anyway, but remember the risk that you're away from home and forgot to turn the heat on when freezing weather comes.

On 2016-05-13 by Cathy

I have two questions. My door to the closet where furnace is has a air vent on it should I cover it on the inside with a filter? My second question is during the winter when I'm using the heater should I turn the switch off in the electric box to the air conditioning unit and in the summer should I turn the heater switch off while I'm using the AC? My unit is a central air/heater combo. Thank you

On 2016-04-16 by (mod) -


If you cannot light the pilot at all then I suspect that there is no LP gas, or no fuel, or a shutoff valve has been left closed.

If you can light the pilot but it will not stay lit then most likely the problem is the thermocouple. That is the flame sensing safety device. If the problem is the thermocouple, that part can be replaced.

Certainly I would not assume that you need to replace the entire heater simply to get it to work.

Be sure that any work done on your heater is buy a trained service person, as making a mistake could kill someone.

On 2016-04-16 by My name is Pam

I have a propane wall heater that I bought from Lowe's I had it installed two Winters ago the pilot light has went out I cannot get no way to come in and look at it and see if they can fix it or to get a new one and install it can you help me please

On 2016-03-21 by (mod) - fan cycles on and off after heat has gone off

Larry: see

On 2016-03-21 9 by larry

have an intertherm m1g mobile home furnace with a blower cycling problem. after the heat is done the blower will start again for about thirty seconds only once each time, but every time. replaced fan limit switch, didn't help. any suggestions?.

On 2015-10-29 by LimeyInPA

I have a 1980s single-side mobile home, with a Miller CMF 80 PO-CONV furnace running oil. The limiter is brand new (installed less than four hours ago), the relay is just over one year old, and the sensor is clean and functioning (tested with a multi-tester).

I am having issues with the furnace coming on, but shutting off BEFORE the fan switches on. Current settings on the limiter are 90/110/160. My home also has a Coleman AC unit which is controlled by the same thermostat, and I am reasonably certain that a replacement thermostat that I installed a few years ago is correctly wired (I followed the markings from the old non-timed unit to the new RiteTemp 6025 unit.

I have the two T-lines running from the furnace to the W and RH contacts on the thermostat

. It is possible that I have the AC connected incorrectly, (were connected on Y and RC contacts on thermostat) but unless this is an essential part of the process of getting things right, that is a low priority at the moment. I am unsure of where to go from this point.

On 2015-06-06 by Anonymous

Why is my duct work condensate?

Question: poorly insulated or uninsulated mobile homes have big impact on heating or cooling costs

(Nov 1, 2011) sandra reddick said:
i have a 1996 moble home trailer and was wonder why it is so cold in the winter time a very hot in the summer. just learning that the moble home has no insulation in it,is that a home code violation.

(Jan 14, 2013) Anonymous said:
weird i hv the same problm i hv a 1968 mobl home it is terrible in the cold the summer is unbearable if u hv no ac units.. is it a violation?


"Violation" is a tricky term Sandra and Anon as building code enforcement is ultimately up to local building officials. More confusion can arise because mobile homes, often built by manufacturers who assume their products must comply with building regulations across multiple states or provinces, build to model codes, and local building inspectors, knowing this, may not feel compelled or even able to inspect such homes for local code compliance.


Question: use a residential heating furnace in a manufactured home?

(Jan 30, 2014) Ray Cole said:
Can a house residential furnace be used in a manufactured home



if by manufactured home you mean like modular housing, not a MOBILE home (trailer home) then yes.

If you mean in a trailer home like the types shown in this article - it depends - on equipment size, space requirements, btu requirements etc. The heater must meet the required HUD specifications.

If you have a specific brand and model in question let me know and I'll research the specifics.

Certainly because space and combustion air and btu requirements are often different for a mobile home like the ones discussed here, we expect to see heating equipment designed for safe installation there.

I'd be very wary about just hooking something up without knowing the specifics as you could risk burning the place down or dangerous carbon monoxide hazards.

(Nov 4, 2014) Anonymous said:
to Ray Cole: No you can not use a residential furnace or air handler in a mobile home. mobile homes are under HUD guide lines. In the installation instructions of residential systems spells this out. most heating systems for mobile homes are down flow and Coleman, Intertherm, Mortex make mobile home heating systems.

However, If you decide to replace the system with a package unit they are compatible as long as they have a high static blower system.

Mobile home duct systems are not design to maintain pressure the further you get from the source.

Question: some rooms in doublewide don't get adequate heat

(Oct 4, 2014) Kathy said:
I have a double-wide built in 2000, my bedroom and bath are in the back of the house and is always so cold from October through the winter/ spring months. The heater is in great condition and I have had an inspector from the gas company check for heat loss, but it hasn't helped

. Could there be a problem under the house with the ventilation pipes and how much would something like that cost to get inspected?

I have had electric heaters in those rooms since I bought the place newly built for me. I have also had the company that built the house come out, but I think they only checked the inside.



The least costly first step might be to ask your heating service company to check for a disconnected or blocked heating duct or a closed register or duct damper.

The check needs to include a complete survey of the ducting, including under the unit.

(Nov 4, 2014) Anonymous said:
Kathy, with double wides typically the heater sets on one half of the home and has a crossover duct to the far half. If your cold rooms are on that far half the air flow and temp is greatly reduced by the time it gets to your rooms. the easiest and first step is to regulate the supply grills on the half the heater sets on.

Cutting almost off any bathrooms (usually the hottest rooms) if the grills are broke replace them, next regulate to at least half off all rooms closest to the heater.

If this does not get the desired results, I would inspect the cross over duct. It should be dead center of the furnace and at least 12" supply. also you can put a scoop (small piece of metal in those vents in the colder rooms to deflect air up. Lastly I would check the seal around the connection of the floor supply boot to the main trunk line it is where to pieces of metal duct join and reseal with foil tape.

Question: clicking noiser but no heat from my electric air conditioning / heating system

(Dec 13, 2014) Robert said:
I live on a double wide mobile home- have an electric air conditioning/heater system. Couple days ago the heater was working and now it does some click noise like is going to come on but do not come on. What could be the problem? Thanks



It sounds as if you have a heat pump that's not working. See the diagnostics at

If outdoor temperatures are too low for your heat pump to provide heat the problem could be failure of your backup heating system to operate. Look for a control board or relay failure.

Question: Triplewide home does not get enough heat in some rooms

(Mar 13, 2015) Ruth Cameron said:
we have a 1997 triple wide and our issue is that both the back bedroom air don't seem to be have any air or heat coming out and we really don't understand of house is cool or warm depending on season.

we have tried to find blue prints of the duct work thru the manufacturer but have been unsucessful, we really didn't want to go to the expense of someone checking it our and telling us that it all needs to be replaced and that it would be very expensive,can you shed some light on this at is very much appreciated



If you are getting air and heat out of some but not all registers then it's not likely that the heating system itself needs replacement. More likely is that ductwork has come disconnected or become blocked somewhere.

On a triple-wide ususally the HVAC ducts are on the underside of the unit. It's worth getting someone with a clear mind and a good flashlight and some knee pads and maybe a helmet to crawl under there to take a look. Not only are you not getting heat in some rooms, but you may be wasting that very heat by blowing it onto the mice under your home.


Continue reading at MOBILE HOME HEATING - home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see these

Heating System Repair Articles

Suggested citation for this web page

MOBILE HOME HEATING REPAIR FAQs at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia


Frequently Asked Questions (FAQs)

Click to Show or Hide FAQs

Ask a Question or Search InspectApedia

Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Comment Box is loading comments...

Technical Reviewers & References

Click to Show or Hide Citations & References

Publisher's Google+ Page by Daniel Friedman