Espar type heater to replace older furnace.

[StirCrazy]

I was just wondering if anyone has chaged out there propane furnace for a diesel type. I am thinking of doing this as my propane furnce is getting old, uses a lot of propane, uses a lot of power, is noisy and had a very wide swing from freazing to roasting. also as it is a direct vent it doen't realy heat up the bed area much.

what I was thinking of doing was getting an espar type heater putting it where the furncase was and use a split outlet to direct a bit of heat up to the bead area while leaving most to go to the main cabing area. was even thinking of maby taking three branches off and put one to the bathroom.

the main question I have is how do you size them? I have a 1991 10foot slumberqueen with a east/west queen bed. there seams to be 2Kw , 3Kw, 5Kw and 8Kw sizes .

also the opinions out there is to get a little larger than you need so it is running at a slower speed using less power, fuel and making less noise. but if you get to large then you will cook your self out running on minimum.

everything I have read (from van sites) shows me they will use 1/3 to 1/2 the power of my present furnace and make a lot less noise.

just looking for real experiances in a TC and advice one way or the other.

thanks
Steve

[StirCrazy]

Photomike wrote:
I have run both. Both have good and bad features, but I am leaning towards my Espar being better then the RV furnaces that I had. Now my Espar is located in my van so this will change a few things then a truck camper.

One of the GREAT benefits is the ability to run multiple ducts BUT even bigger for me is having a cold air return. I can take cold air from the coldest part of my vehicle and heat it. My RV furnaces all took air from the front of the furnace to heat and with them being a foot or two from the floor the floor was always cooler. Maybe other units had this ability but my two units did not.

I like that my Espar uses gas as it stays liquid in extreme cold better then the propane. I like only having one fuel to worry about in my van. Using one of the diesel units with separate fuel tank would work but I would be back to two fuels to make sure were topped up.

Inside noise I would say is a little quieter then the propane. Maybe half the noise on my worst RV propane unit and a quarter on the less noisy one I had in my RV.

BIG issue is the noise on the outside. The Epsar is like a CF-18 kicking in the afterburners when it fires. Does keep people from camping on that side of me. Maybe an issue if you run it in a campground.

Myself I would not put a duct in the cab over. Heat rises and it would get REALLY toasty up there.

A second thought would be a vented cat heater if you are looking for quiet.

stack two mufflers, the strait type not the offset and it cuts the outside noise down to the low 50's which is way quieter than any propain furnace I have had.

Cat heater is out of the question, I want combustion air to be totaly seperat from the heating air. there is a reason they are not factory in rv's anymore pus with the dog and a grandkid I dont need singed hair or burnt fingers.

[StirCrazy]

HMS Beagle wrote:
Propane RV furnaces with ducts are common. Cold air return is available, but less common.

The Espar/Webasto type heater can be VERY load outside. These heaters are common on boats in the PNW. The worst of them will keep the whole anchorage awake at night. The best sound about like a propane RV furnace. It depends somewhat on the installation, manufacturers offer mufflers for the exhaust.

ya if some one doesnt use the mufflers, with two stacked straight through mufflers they are only 52 decibels and that was on a 5K unit, I bet my propain furnace in the 5th wheel is in the mid 60's.

Steve

[StirCrazy]

Photomike wrote:
They do have mufflers for them. The diesels I have heard a lot of people say that the mufflers cause problems. Likewise high altitudes can cause issues without the high altitude kits.

Some of the newer diesel pushers use these as well. They can run the ones that preheats the engine or for air heat.

is isnt the mufflers that are causing the issues if you use the straight through ones, but rather how they run the exhaust. that seams to be the biggest thing that causes issues in them is the exhaust and intake running.

[towpro]

we did just have a large 5er parked near us last month that the propane heater sounded like a jet engine running.
I also know a hot water heater can be noisy if the burner tube is not adjusted right.

[Photomike]

They do have mufflers for them. The diesels I have heard a lot of people say that the mufflers cause problems. Likewise high altitudes can cause issues without the high altitude kits.

Some of the newer diesel pushers use these as well. They can run the ones that preheats the engine or for air heat.

[Kayteg1]

Somebody made those heaters portable in separate box.
video presentation

[Kayteg1]

I had complains from campground neighbor that my water heater kept them awake.
Few years back we camp at RV park and 4 sites away there was pretty expensive Class A.
His furnace was so loud, that having no other RVs between would wake us up at night.
I talk to the owner and he said it was new RV with all warranties still valid and his service said the noise is normal for the type of furnace he had.
With diesel heater it is exhaust pipe that makes the noise.
That can be short or long, some of them come with muffler, so you can easy control it.

[HMS_Beagle]

Propane RV furnaces with ducts are common. Cold air return is available, but less common.

The Espar/Webasto type heater can be VERY load outside. These heaters are common on boats in the PNW. The worst of them will keep the whole anchorage awake at night. The best sound about like a propane RV furnace. It depends somewhat on the installation, manufacturers offer mufflers for the exhaust.

[Photomike]

I have run both. Both have good and bad features, but I am leaning towards my Espar being better then the RV furnaces that I had. Now my Espar is located in my van so this will change a few things then a truck camper.

One of the GREAT benefits is the ability to run multiple ducts BUT even bigger for me is having a cold air return. I can take cold air from the coldest part of my vehicle and heat it. My RV furnaces all took air from the front of the furnace to heat and with them being a foot or two from the floor the floor was always cooler. Maybe other units had this ability but my two units did not.

I like that my Espar uses gas as it stays liquid in extreme cold better then the propane. I like only having one fuel to worry about in my van. Using one of the diesel units with separate fuel tank would work but I would be back to two fuels to make sure were topped up.

Inside noise I would say is a little quieter then the propane. Maybe half the noise on my worst RV propane unit and a quarter on the less noisy one I had in my RV.

BIG issue is the noise on the outside. The Epsar is like a CF-18 kicking in the afterburners when it fires. Does keep people from camping on that side of me. Maybe an issue if you run it in a campground.

Myself I would not put a duct in the cab over. Heat rises and it would get REALLY toasty up there.

A second thought would be a vented cat heater if you are looking for quiet.

[HMS_Beagle]

Efficiency of a furnace is Heat Out / Fuel In.

But thermal efficiency in an RV furnace is really not that important. More important may be noise, fuel availability, AH requirements, installation volume, among others. In my opinion an Espar/Webasto (or better still a Wallas) is a better option than the typical Rv furnace, held back by the need for a separate diesel tank when most RVs already have a propane system. Better even than that would be a Webasto or ITR hydronic, which solves the domestic hot water issue as well. Wallas even makes a diesel stove, you can get rid of the propane altogether.

[S_Davis]

Fuel has a given value so without burning it in a heat exchanger you can’t get combustion efficiency, all the test equipment I know of measures air temp in and out of the equipment as well as flue gas sampling for o2, c02, and co, so combustion efficiency takes into account the Individual heat exchangers.

[Kayteg1]

S Davis wrote:

HMS Beagle wrote:
On the other hand, no way a diesel Espar type is going to be 90%. To get into the 90s a heater has to be condensing, and they are not even close to that.

Getting 87% combustion efficiency is fairly normal on oil, there are even blueflame burners that are in the low 90% range that are non condensing.

Combustion efficiency doesn't mean much when you couple it with lousy heat exchanger.

[S_Davis]

HMS Beagle wrote:

S Davis wrote:

HMS Beagle wrote:
On the other hand, no way a diesel Espar type is going to be 90%. To get into the 90s a heater has to be condensing, and they are not even close to that.

Getting 87% combustion efficiency is fairly normal on oil, there are even blueflame burners that are in the low 90% range that are non condensing.

I'd be shocked if an Espar/Webasto type hot air heater could achieve that efficiency. Yes, maybe a large home unit. Looking at the specs, one model for example uses 0.23L/h while producing 6150 btu, that is an efficiency of about 73%. A decent propane furnace is probably around the same, or maybe a little less.

No argument there, I have not had the chance to hook up my combustion test equipment to one yet. It was the statement about having to be a condensing unit to get to 90% efficiencies that I was responding to. I will be converting to diesel heat and hot water, I am going hydronic radiant heat to get rid of the forced air.

[StirCrazy]

noteven wrote:
StirCrazy - 17000 btu/hr = 4.98 kw /hr.

RV furnaces are probably 80% efficient.

“Diesel heaters” are probably 90% or better...

Diesel fuel has approx twice the power density of liquid propane. Winter diesel is 20% less than summer diesel.

I.e 1kg or 1 litre of diesel fuel has 2x the heating energy as 1kg or 1 litre of LPG.

And yes electricity use is way less per hour...

I would place the old direct vent furnaces at around 60% when new, probably less now. mine is a 12K input 10K output but I think thoes are test conditions, also says it is only 1.6 amps but I measure 3ish

a 3Kw unit would give me roughtly the same max ouputbut at around 0C my furnace was cycling on and off every 2 min, so I imagin if it was colder it would run full blast .

if I can find a 4Kw model it will have a rank from 3070 Btu on low to 13648 Btu on high, for a 5Kw unit it would rng from 5459 Btu on low to 17060 Btu on high.

so now I have to try figure out which unit will stay running on low most of the time with out shutting off and turning on as thats where they use the most power on the ignition phase, but wont roast me out in the late spring and early fall, but still provide enough heat for that once and a blue moon I would go caming in the winter.

I think a 4Kw model is the front runner right now, 3000Btu more than my curent heater but able to drop pretty low

Steve