Making an rv furnace quieter

[ksbowman]

Every rv furnace we have ever had was noisy. Has anyone done something to quiet there furnace. I have considered trying to wrap the blower area in insulation. Anyone had any luck?

[Blazing_Zippers]

A few years ago, I blocked the heater opening off, cut out some cabinet walls (under the drawers), and placed a grill opening a few feet away from the furnace. The air flow was still very adequate and the furnace fan noise was quieter.
Another trailer, I placed two insulation baffles between the opening and the living area. The air flow had to weave around the baffles somewhat---very nice.
Currently, I'm still scratching my head about this trailer.....

[rhagfo]

gwalter wrote:
I added the Cheapheat furnace system to our furnace. It uses a 5000 watt electric element for heat. It still uses the furnace fan which is not very noisy without the propane burner running. We love it and the comfort of the heat. You still have the option of running propane heat if you wish.

Link

X2

Safer than electric space heaters and catalytic gas heaters. speaking of possible hot surfaces, and heavy current draw on minimal electrical wiring, in addition catalytic place large amounts of additional moisture in the RV, causing condensation. My dad was a Firefighter and saw way too many fires caused by space heaters, and deaths from depleted oxygen.
That and space heaters do nothing for keeping the basements warm.

I currently have our Cheap Heat system stepped down to 1,800 watts as we are on a 30 amp service, we have gotten down to the low 40's and it still keeps us warm, just needs to run longer.

The only issue I have with it is, if one runs on electric for an extended period, the first time you switch back to gas, is the stink of burning dust off the heat exchanger.

[noteven]

wopachop wrote:
So for both Buddy and Olympian you need to open a window to vent?
Is there any other option for a quieter and more efficient propane heater?
My furnace is loud and seems to suck up propane real fast.

In my unedumacated terms:

Not to “vent” combustion (rapid oxidation) but to provide a supply of oxygen. I do not have chemistry credentials so dare not be too specific, but these types of heaters are a “catalytic converters” using O to convert the C and H in propane into C02 and H2O. Radiant heat is the quiet by product. Water vapour is a by product that has to be managed. High fuel efficiency is also a benefit.

Keep in mind radiant heat warms people and materials in a steady manner not air blowing about. Think warming a rock with the sun or a hair dryer...

Radiant heat travels in straight lines, but if you leave it alone it warms the partition wall and then the closet behind and so on.

A bit of venting management is a fair trade for the comfort.

I can place my CO monitor above my Big Buddy heater at start up or running reading = O. Not so above you propane stove or furnace exhaust.

The rv furnace is excellent in cold rainy weather because heating air quickly reduces the clammy humidity. In cold dry weather (desert winter nights) radiant heat and the comfort of warm materials around you is nice.

If you like to throttle heat up and down all the time hot air blowers are a better choice.

[Blacklane]

fncampn wrote:

Dutch_12078 wrote:
The majority of the sound from our two furnaces comes from the large cold air returns. I lined the area behind the grills with a sound absorbent material, and even blocked off a section of the over sized grill with the same material, being careful to still exceed the manufacturer's required minimum opening area and minimize restricting air flow. The sound level reductions were significant, although I didn't take any before/after measurements.

Instructions for the mod Dutch made can be found here: Soundproofing a noisy furnace

For "Sound Absorbent Material" for this mod, I would use acoustic foam panels readily available on-line and elsewhere. They are usually egg-crate, pyramid, or ridged foam panels about an inch thick. Make sure they're flame proof. They are amazing at absorbing sounds, particularly at the frequency of most fans. You can glue them to the inside of the furnace cabinet, of course keeping away from the actual furnace.

If your cold-air grate has the typical 10" x 20" opening (200 square inches) and your furnace requires the typical 80 square inches of return air area (see the manual for your furnace), then I would use an acoustic foam panel to block half of the cold-air grate, which allows about 10" x 10" or 100 square inches.

[wopachop]

So for both Buddy and Olympian you need to open a window to vent?
Is there any other option for a quieter and more efficient propane heater?
My furnace is loud and seems to suck up propane real fast.

[fncampn]

Dutch_12078 wrote:
The majority of the sound from our two furnaces comes from the large cold air returns. I lined the area behind the grills with a sound absorbent material, and even blocked off a section of the over sized grill with the same material, being careful to still exceed the manufacturer's required minimum opening area and minimize restricting air flow. The sound level reductions were significant, although I didn't take any before/after measurements.

Instructions for the mod Dutch made can be found here: Soundproofing a noisy furnace

[gwalter]

I added the Cheapheat furnace system to our furnace. It uses a 5000 watt electric element for heat. It still uses the furnace fan which is not very noisy without the propane burner running. We love it and the comfort of the heat. You still have the option of running propane heat if you wish.

Link

[nayther]

the more "bends" you can make for the air the quieter it will be but too many adds pressure drop and may reduce air flow. Keep the velocity below 400 ft/min and all will be fine.

[noteven]

MNGeeks61 wrote:
To my knowledge, the Buddy heaters are not catalytic but they are efficient. Still need to vent for safety as improper combustion results in CO.

They have had oxygen sensors in them since... 2000 I think? So if there is limited oxygen they're supposed to shut off.

Buddy heaters are catalytic.

I use a Big Buddy - it has 1lb disposable cylinder connections, and quick connect for trailer system direct connection with a hose, or you can connect to a cylinder. It stands on it’s own so is portable. You can direct the heat where you want it. It would be bulky in a small floor space. The catalytic reaction consumes oxygen and produces water vapour so you must vent the space. I open a lee side window a bit and a roof vent. It is very efficient. I test my CO detector above stove burner from time to time. It registers a steady 0 held above the cat heater. It is a great heater in low RH weather. If raining or foggy you need to manage the humidity properly.

Mine cost around $200 for the heater and to rig with a hose and quick connects.

Fizzles a bit on low, pretty much silent on mid or high setting.

Low technology.

[camperkilgore]

deleted

[Almot]

In a living room of a trailer the blower is usually very close. In a small box of trailer the sound of blower reverberates from the walls and also transmitted through the vibration of the wall where this evil machine is sitting, and through the floor too. Maybe in a 5-er in a bedroom it will be quieter because you are on a different "floor" and are sheltered by interior wall. Cycling in the night is most annoying, worse than a steady noise.

On hookups I would use fan-less electric convection heater like a small baseboard heater or electric fireplace. On offgrid - propane heater, with one CO detector in living room and another one added in bedroom, with windows and/or vents slightly open as per instructions. In warmer climates you can often avoid running heater (or furnace) in the night, it's only needed from sunset to bedtime, and another hour in the morning. Get a good warm duvet.

[nayther]

What we hear is the blower. In most installations there's a direct line of sight to the blower on the furnace, that's what you hear. If you can "break" that line of sight without choking off air flow you will greatly reduce the sound, sound travels in a straight line and doesn't "bend". On residential furnaces I've used fiberglass ductboard to redirect the air, place the board so the fiberglass faces the blower which helps absorb the sound. Sometimes there's enough distance behind the return grille to suspend a piece of ductboard, directing the air around the edges and blocking line of sight.

[MNGeeks61]

To my knowledge, the Buddy heaters are not catalytic but they are efficient. Still need to vent for safety as improper combustion results in CO.

They have had oxygen sensors in them since... 2000 I think? So if there is limited oxygen they're supposed to shut off.

[Almot]

ksbowman wrote:
Every rv furnace we have ever had was noisy. Has anyone done something to quiet there furnace.

My solution: Olympian Catalytic Heater, permanently mounted on the wall. Drilled one little hole in the floor and tapped copper tubing into black iron pipe underneath. The only part (other than 1/4" tubing) was a brass Tee to install onto black pipe where similar copper tubing was branching off to water heater.

Furnace is now "dead" quiet. Very easy on propane and zero 12V draw. Perfect for offgrid on solar.

A tip to those considering Olympian: if your temps are above freezing - SoCal, South AZ or wintering in Mexico - get the smallest 3,000 BTU model. I got 5,000 BTU for 26 ft trailer, this was too much, even on Low it raises temperature quickly, and there is no thermostat - only High-Med-Low.

Somebody mentioned Buddy heaters - I recall they are not catalytic, though I might be wrong.

If you are on hookups, you might consider electric heater. Fanned electric heaters can be annoying due to noise and feeling of "draft", but there are also fan-less heaters: 1500W Baseboard heater with thermostat. Amazon have some too. They are ~2ft long.