Shop Heater

[pmsmechanic]

Confused. Is there no circulating fan in the heater?

There is, it just doesn't run when the power is off. The firebox cycles on and the high limit switch turns it off. It just keeps cycling that way untill the power comes back on and then you have a regular furnace.

I would stop listening to who ever told you that. It's pure rubbish.

So in December I burnt 18.2gj's (gigajoule) of gas. Admittedly we are having a warm winter so let's bump that up to say 25gj's. So 25 x $2.90/gj = $72 for the month of December. The difference in efficiency's is around 30% so let's multiply $72 x.3 = $21.60/month difference on the price of gas burned. For the sake of argument lets just go x 6 months as we don't use the furnace in summer. So $21.60 x 6 = $129.60/year savings between the two furnaces. In 10 years that works out to $1296. So show me how I can pay for a furnace in 10 years. I'd really like to know. Admittedly there might be something wrong with my math so feel free to check it out.

 

[Carl_NH]

So 1GJ of gas is equal to 10 gallons of propane, or 7 gallons of fuel oil equivalent. 18gj then is 180 gal of propane which in our area is $1.70/gal = $300/month and for fuel oil it would be $250. @ $2 per gallon. These are the prices in our area and it differs around the country.

So if you apply the same math with a 30% savings it would be $90/month savings for propane, and $75/month for fuel oil. So for 6 months roughly $500/year on average and over 10 years $5000.

We put in a new 91% efficient oil boiler in 2009 and went from 900 gal to 550 gal per year and fuel oil has ranged from a high of $4 a gallon to $2 now and our ROI was less than 5 years.

Agreed, your savings depend on what fuel is available in the area and cost of that fuel and it varies widely across North America.

 

[Slowpoke Slim]

There is, it just doesn't run when the power is off. The firebox cycles on and the high limit switch turns it off. It just keeps cycling that way untill the power comes back on and then you have a regular furnace.



So in December I burnt 18.2gj's (gigajoule) of gas. Admittedly we are having a warm winter so let's bump that up to say 25gj's. So 25 x $2.90/gj = $72 for the month of December. The difference in efficiency's is around 30% so let's multiply $72 x.3 = $21.60/month difference on the price of gas burned. For the sake of argument lets just go x 6 months as we don't use the furnace in summer. So $21.60 x 6 = $129.60/year savings between the two furnaces. In 10 years that works out to $1296. So show me how I can pay for a furnace in 10 years. I'd really like to know. Admittedly there might be something wrong with my math so feel free to check it out.

No. Do the math any way you feel like. Whoever told you that you HAVE TO replace a "modern furnace" every 5 to 10 years is out of their mind. 5 to 10 years? For a furnace. That is rubbish. Spin the math anyway you like. If my contractor couldn't get more than 5 to 10 years out of a furnace, he'd get bounced down the road.

 

[pmsmechanic]

I've heard of more than one "new" furnace that needed to be replaced as the firebox was cracked. Especially on the early high efficiency furnaces that were installed. If the manufacturer has gone out of business there is no choice but to replace the furnace as parts are not available.

And just for the record I'm a board member of a gas co-op. I do hear about the furnaces that don't work out. I do know what it costs to install a new furnace as I've seen the bills. As a co-op we had a bit of a learning curve as to how much quality was built into furnaces by some manufacturers.

Anyways back to the op's thread. If someone is interested I can find out which brand of furnace we now install at the co-op.

 

[Milo]

I have a 30x40 insulated shop with no natural gas. Anyone have good experience with a specific LP or electric heater that won't cost an arm and a leg to purchase and operate? Thanks!

I recently built a shop about the size of yours (28' x 38') which consists of three rooms, 24' x 28', 14' x 12', and 14' x 16'. It only has one double door 7' x 7', 6 small 36" x 12" windows, is well insulated with 2' foam under the slab, 5 1/2' spray foam in walls, about 10-12" on the attic floor, so low heat loss, and LED lighting. I heat and cool it comfortably with a single Carrier mini-split in the large room leaving it at 62 in Winter and 74 in Summer. Power for it comes from my 1,700' all electric house which is well insulated, with an 18 year old heat pump. My December 2019 power bill house only was $71, December 2020 with the shop added it was $97. So about $26 for heat, it wasn't frigid cold last month but had a little snow on the ground most of the month. I don't know how much the Carrier mini-split cost as it was part of the overall shop build bid.

 

[ultrarunner]

A natural gas service man and I figured it out once in the difference between what I was using now in gas with my 1960's furnace (60-70%) vs buying and installing a new mid efficiency furnace (90-95%) at $4000. Considering that the new furnaces need to be replaced about every 5-10 years there is no way that I could ever pay for a new furnace in gas costs alone. So we decided to leave my furnace the way it is. The bonus is that it's still an old millivolt system and will cycle the furnace on and off even with no power so I don't have to be concerned with my house freezing up during a power outage.

Yep... went through the same here and with the mild climate not many heating days anyway.

1922 home of 1150 square feet...

In the basement a huge millivolt gas central furnace that is similar to coal of that vintage.

The ducts are huge and heat circulates via convection...

Can't tell you how many envied that furnace... totally silent heat... not like the dust blowers of the neighbors where the curtains start blowing and best part was when earthquake took out power for 8 days I had heat, hot water and cooking...

Just replaced a fried circuit board on 16 year old ammana today... no heat since New Years Day... Board actually came on 12th but with daytime temps in mid 70's ok.

Last year had no heat at another rental... 9 year old hi efficiency with bad ballast.... not able to get one on Thanksgiving.

June replaced bad blower on another one... Expensive variable speed $600+

Then I think of all the key match light floor furnaces I have over 100 years old with zero issues as well as wall furnaces... keep a few thermocouples on truck and quick fix.

Maybe if heat or cool climate savings more important.

My 5 year old 14k heat pump in Olympia WA costs a couple of hundred each year so far... which comes out of my pocket... The old resistive furnace had zero issues except tenant complaints expensive to operate

Flame Sensors, Draft Inducers, Draft Sensors, Roll Out, etc... povide many avenues to cause no heat...

 

[redheelerdog]

My Mr Heater Big Max is going on its 2nd winter running on LP in a 30X60 steel building.

I really like this heater and it is great on fuel. Bought mine for $400 two years ago, comes with a LP conversion and thermostat. I am running it off a micro smart TS now and what's nice is I can fire up the heater with my phone 20 mins before I go out to the shop if it is really cold.

MHU8 Big Maxx Natural Gas Unit Heater | Mr. Heater

I also run 2 - 1500W milk house heaters 24-7, if it does not get sub zero it never drops below 50F.

 

[3Ts]

How tall is your steel building and how much insulation do you have?

 

[redheelerdog]

How tall is your steel building and how much insulation do you have?

16'-9" at the peak, 13' walls, R19 roof and walls.

It was 8F here last night and the shop got down to 51 with the two milkhouse heaters this morning. Cranked up the Mr heater and it was 62 in about 10-15mins.

 

[redheelerdog]

Her's my 2 little milkhouse heaters