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Mobile home heating & air conditioning systems:
How to Inspect the heating and cooling systems in mobile homes, trailers, double-wides, multi-wides:
How to spot common and dangerous defects in heating equipment incuding furnaces and boilers, inadequate heat distribution, freeze-ups, and safety hazards.
How to save heating or cooling costs for mobile homes and trailers or multi-wides. Page top sketch was provided courtesy of Carson Dunlop Associates, a Toronto engineering, education, and home inspection company.
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(Aug 29, 2012) Maxine Payne said:
The red tag was apparently covered up when vinyl siding was installed. Now I want to sell the property, but I can't because I do not have the red tag number. How do I get the red tag number?
(Aug 29, 2012) Greg Filian said:
The flashing of the lights mentioned are they in the whole house or just one outlet? If it's just one outlet it may be just the outlet, if it's the whole house the problem may be at the main connection.
(Sept 8, 2012) Gail said:
I am looking at buying a double wide through an estate sale. The "trustee" of the estate is the deceased owners daughter, who know very little to anything about mobile homes (as I).
I am hiring an inspector, how ever he wont be available for 3 weeks and I have an immediate concern...
While standing in the living room I was startled out of my skin to see a cat jump into the living room from a floor vent ( vent cover was pulled off) I looked into the vent and it appears to be completley open - no duct work - just a view of the ground beneath. The daughter said that that was common and is there for ventilation. LOL Tell me this isnt so!
Thank you SO much for the wonderful cat - HVAC system question.
Yes I can tell you "it isn't so" - that is, it is not good practice to simply leave floor vents in a home open to the outdoors such that anything, including a cat (or worse, a raccoon) can hop in for a visit.
I can imagine a few reasons why you might have found the missing duct work and open floor vent, all adding up to some more trouble and work for you. For example most likely there was a heating or heating and cooling system that used air but that has disintegrated, been damaged, fallen off, or was simply removed and abandoned.
Sometimes too, when warm or cool air delivery into a home is poor in flow rate or quantity, people try to improve system operation by adding more return air to the system by just cutting an opening that lets outdoor air into the system somewhere. The problem is this is the most expensive possible way to heat or cool a home since it's a "one way" design - we take un-conditioned air from outside, heat it or cool it, then try moving it into the living area.
Really the most significant implication of the cat in the hat, I mean cat in the vent discovery in your possible future home's heating sysem is that it's a red flag to watch out for other work done or "problems solved" by the same person on that home - as you may find other amateur workmanship that lengthens the list of repairs and improvements needed to make the home safe and habitable to normal standards.
Keep me posted, and send along photos if you can (use the CONTACT US link at page bottom or top) - especially if ... the cat comes back.
I suppose a less ridiculous explanation that the owner could have invented might have been to explain
"Oh I forgot to tell you, that's just Marion, my mom's cat. Marion comes with the house. The hole in the floor is her pet door."
Below our photographs illustrate several unsafe conditions at a house trailer's heating system inspected by D Friedman & S Vermilye during a mobile home site safety investigation. Notice that when the door to this central air handler is closed return air from the occupied space cannot reach the equipment.
In addition to the absence of return air to the heating furnace we notice that
Why does my doublewide always feel uncomfortably warm especially at night when trying to sleep and even with the temperature at 70 to 71 degrees? - Daniel Phipps 4/16/2012
Daniel that question has me stumped. There are so many possible reasons:
- a medical problem
- windows shut
- no ventilation
- bedroom close to a heating appliance that is "on" such as a water heater
- air conditioning system that is not working properly, has a blocked filter, blocked cool air return, dirty blower fan, etc. - see MOBILE HOME COOLING SYSTEMS discussed here
Check your own sensations against actual room temperature - I'm not sure if that's what your comment about "even with the temp .." meant.
I have home owners insurance, and it says it covers "accessible ductwork from the air condtioning unit to the point of attachment at register" what does that mean? Is my ductwork under the house covered? - Anonymous 7/17/2012
Discussion of "accessible" building components vs inaccessible
Anon: re "accessible ductwork" - indeed that word has been the subject of lots of debate - the final answer lies with your insurance company and perhaps the onsite tech. Generally for building inspectors the term "readily accessible" is used to mean that the component can be approached, seen, touched, without having to cut anything apart or disassemble anything not intended to be opened by a homeowner.
For a service technician, "accessible" means it's reasonably possible to get to it - in my OPINION - without having to cut holes in ceilings, walls, floors. So if "under the house" is an area that can be physically accessed, say by entering a crawl space that is not itself so tight or unsafe as to be not enter-able, then in my OPINION the ducts are accessible.
When we debated this question at a home inspection association it was after an inspector had fallen to his death while crawling up a building-mounted but loose roof access ladder. He felt that he HAD to access the building roof but there was no other means for him to do so. He was killed.
A result of that terrible experience was a decision that ultimately we do not ever want to demand that anyone, inspector, nor service technician, attempt to "access" a building component or area if s/he has a reason for not doing so, such as a personal judgement about safety.
However that doesn't mean that a problem needing attention goes forever ignored. Rather it means that ultmately arranging safe functional access may take more time, trouble, and special arrangements. And cost accordingly.
Readers should also see MOBILE HOME PLUMBING where we further discuss oil tanks, oil piping, and water heaters for mobile homes. Page top sketch courtesy of Carson Dunlop.
23 January 2015 Chuck said:
I have a doublewide mobile home with the air ducts in the cieling. A rat has gotten into the air duct and chewed insulation and now insulation is blowing through the vent. I am going to have a company put a camera up there to find the break so it can be fixed. My question is would it be easier for me once I knew exactly where the break was to just go in from the roof. It seems alot faster and less expensive than tearing out the cieling and replacing sheetrock, tape and bed and repainting, not to mention the mess in the house. What are your thoughts?
If your doublewide has a conventional continuous metal roof over an inaccessible space then you won't do well trying to cut into the roof and you risk creating a point of future roof leaks. I'd be inclined to work from the interior. But then I haven't seen your home.
If there is an attic access (which some doublewides have) then of course it'd make sense to get into that space and remove and replace the ductwork and any contaminated insulation.
Further, if there were rats in the ductwork, you want to replace ALL of the ductwork and insulation where rats were nesting lest their pee and poop and other debris become a health concern later on.
This topic has moved to a separate article at MOBILE HOME INSULATION
Full text of the manufactured and mobile home heating standards can be found in
PART 3280—MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS [PDF] newer copy retrieved 2017/07/13 - faster-loading
See Subpart H, Heating, Cooling and Fuel Burning Systems in that document.
Updated through January 2018 - Steve Vermilye, New Paltz NY and Daniel Friedman, Poughkeepsie NY, Hudson Valley ASHI Chapter Seminar, Newburgh NY, January 4, 2000, NY Metro ASHI Fall 99 Seminar, Holiday Inn Crowne Plaza, White Plains NY, October 2, 1999.
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(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.
Please see MOBILE HOME INSULATION
(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.
(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.
(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.
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