Replacing old units, savings?

[FunkyfullWidth]

I'm renting some shop space that has two old natural gas heaters. They're both modine heaters. The big shop has a 180k or so and the smaller shop has a 80k give or take. Last years gas bills were around 100 for the small shop which I left at 50 all season, and 450 or so per month keeping it at 65 and down to 50 at night. Shop sizes are 50x50 20 foot at the peak fully insulated and a 30x40 block construction.

I want to replace both heaters with something more efficient. Should I see a noticeable change in gas usage if I go with a more efficient heater? The current heaters look like late 80's early 90's units and have never been maintained.

 

[finn]

I suspect poor insulation and heat loss are bigger issues than heater efficiency.

Even new hanging unit heaters have efficiencies in the low 80% range.

 

[HoosierBuddy]

I'm going to take the opposite view of finn (sorry finn!)

If you have a lot of heat loss, you can save even more money by replacing the unit heater...because they run more.

The old Modine hanging heaters we had around here from the 70's were likely more in the 60% efficiency range based on the fact they were probably over-rated in the day and by the time we replaced them they were long-past due. Of the 3 I replaced, all seemed to be working OK, but upon inspection, every one had huge cracks in the heat exchangers.

I replaced them with Modine's effinity line of hanging heaters. Those are fully condensing units and operation at over 90% efficiency. Based on that, I expected to see 1/3 savings...and that's about what we got.

If I was going to ballpark the savings from a 70s era hanging heater...I'd assume 60% and if the new heater was 80%, I'd estimate a 20% savings.

Will it pay for a new heater? Over time it will. If you check out the heat exchangers....you're very likely to find them cracked if the unit is really old....and you shouldn't use them like that.


BTW...If you are renting and the heaters are the landlord's, an inspection showing a cracked heat exchanger would likely be all you'd need to make the owner repair or replace them....and replacement is the more likely option.

Phil

 

[Stuart in MN]

I want to replace both heaters with something more efficient. Should I see a noticeable change in gas usage if I go with a more efficient heater? The current heaters look like late 80's early 90's units and have never been maintained.

If they are from the 80s or 90s they should have an energy savings sticker on them. Look for that, and then compare it to the information on a new heater so see how much difference there is.

 

[finn]

I do agree with Hoosier, if in fact the old heaters are the ancient 60% ones, but I wouldn’t upgrade until I did a heat loss map with an infrared camera.

 

[FunkyfullWidth]

BTW...If you are renting and the heaters are the landlord's, an inspection showing a cracked heat exchanger would likely be all you'd need to make the owner repair or replace them....and replacement is the more likely option.

I figured someone would say that. He's the cheapest guy I've ever met. He won't replace anything and if he did it would be something far worse probably just as old that he bought off his scrap guy for 40 bucks. He claims the newer efficient units are a scam and don't work. I've already conceded to this and figure over a few years I'll pay for the units with the savings anyway.

Phil

If they are from the 80s or 90s they should have an energy savings sticker on them. Look for that, and then compare it to the information on a new heater so see how much difference there is.

I did not see a sticker, so perhaps they're older than that. I doubt he bought them new either way so the age of the building is moot.

 

[yeldogt]

I can't really understand the shop sizes from your post ... but it really does not matter. Get all the dimensions and figure out the heat load of the building and that should give you an idea of the degree days and amount of heating. You can use those numbers to determine the usage and compare.

Also, is the building really dropping 15 degrees over night? at what outside temp.? Do some reading ... that't a big drop and often not saving any $$. The heaters need to run in the am to make it all back up -- and heat the items that have cooled.

 

[Miss the Pontiacs]

Let me understand what you are doing. You are willing to upgrade heaters with your own cash. Saving a fraction of what the heaters are going to cost. Are you renting for extremely cheap or are you planning on renting for years to come. Would the landlord do the upgrades since the heaters are worn out, or at last share the costs of heaters, permits etc?

 

[FunkyfullWidth]

Let me understand what you are doing. You are willing to upgrade heaters with your own cash. Saving a fraction of what the heaters are going to cost. Are you renting for extremely cheap or are you planning on renting for years to come. Would the landlord do the upgrades since the heaters are worn out, or at last share the costs of heaters, permits etc?

My rent is fair. My landlord won't replace anything. I won't even suggest him covering costs of any kind. He's a different kind of breed. Not many people get along with him. But, I plan to stay a while. The location is great and the property is awesome with plenty of room for growth. He's mentioned selling a few times and I've mentioned buying.

I figured comments like this would come up because it should be up to the landlord to supply things of this nature. He won't. I moved into this place and it had NO LIGHTS, minimal outlets on the wall. Just outlets on the ceiling so we could plug our own lights in. There's 7 units in this building, but 3 electric meters. I've battled on seperate meters since I moved in. Some people you just can't argue with. If there had been a better place available I might have considered it. But i'm currently in the middle of everywhere I want to be and not far from a few of my biggest clients.

Either way... I want what I want. And what I want is a nice, quiet heater that doesn't cost a fortune to run. Plus the way I see it. If I save 100 bucks a month for a heating season the usually lasts a minimum 4 1/2-5 months i'll be break even in 3 years or less depending.

 

[Miss the Pontiacs]

Makes sense then, especially after your last paragraph. You do have a return on your investment with your fuel consumption. Being handy to your clients is also worth time and money.
Hopefully your landlord does appreciate you being a good tenant and sells the property to you.
Good luck

 

[James-W]

I am sure the newer heaters will be more efficient, but whether or not they will save you $100 per month, that remains to be seen. I don't think a new heater will save you that much, but I could be wrong on that. I guess the only way to tell for sure is to get a new heater and try it out.

 

[SALIV8]

Often local utility companies offer free assessments and other rebates as well. I'd start with them and see what their calculations come up with.

Plus the rebates are usually a decent amount also.

 

[Jim greengo]

How hard would it be to add some insulation?

 

[danski0224]

I'm renting some shop space that has two old natural gas heaters. They're both modine heaters. The big shop has a 180k or so and the smaller shop has a 80k give or take. Last years gas bills were around 100 for the small shop which I left at 50 all season, and 450 or so per month keeping it at 65 and down to 50 at night. Shop sizes are 50x50 20 foot at the peak fully insulated and a 30x40 block construction.

I want to replace both heaters with something more efficient. Should I see a noticeable change in gas usage if I go with a more efficient heater? The current heaters look like late 80's early 90's units and have never been maintained.

If the existing heaters are serviced and brought up to spec, the savings will be small... if anything.

Heat rises, so a few ceiling fans will help.

If there is the ceiling height, an infrared tube heater will cost far less to run than a forced air unit heater.