# electric garage heater



## nailkiller1 (Jan 15, 2009)

Can somebody recommend a electric heater for a garage to be on off peak


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## woodchuck2 (Feb 27, 2008)

Maybe install one of these on a timer http://www.heater-store.com/garage_heaters_electric_utility_heaters_dayton_3ug74_1446_prd1.htm , size of the unit needed would depend on size of garage and how well it is insulated.


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## 480sparky (Feb 1, 2009)

I'd check your present power capacity first to see how much amperage is available. Then see if that's enough to drive what you need for heat.


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## nailkiller1 (Jan 15, 2009)

Have you installed a dayton unit before


Power is not an issue it is a new house


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## 480sparky (Feb 1, 2009)

When it comes to electric heaters, there's no difference in efficiency like there is with gas furnaces. All electric heat is 100% efficient. Every watt consumed is converted to heat. A 1000w heater that costs $100 will cost the same to run as a 1000w heater that costs $500.

So it's a matter of control, aesthetics and cost.


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## SummitRemodel (Mar 18, 2009)

*Just installed one*

I just put in a dayton 5000w 240v in an 800 sq ft insulated outbuilding I did for a customer. Super quiet. Internal thermometer. Have it set to kick on when the garage temp drops below 50. A little undersized for my application but keeps the garage comfortable even in this kansas city winter. Think I paid 300.00 for it and would buy it again. It raises the garage temp about 10 degrees every half hour when its real cold but wont heat the garage above 65 but why would you want a workshop warmer than that.


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## GettingBy (Aug 19, 2010)

SummitRemodel said:


> 5000w 240v in an 800 sq ft insulated outbuilding I did for a customer.
> 
> wont heat the garage above 65


One rule of thumb is 10 W per sq. ft.

What's your outside temp when the heater is giving you 65 F inside? 
This is the point at which the 5000 W heat input exactly equals the heat loss through the insulation, assuming no heating from sunlight.


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## SummitRemodel (Mar 18, 2009)

If the outside is low 30's it will get me to 65. Anything below that and it stays in the 50's. But again...not needing it to smoke anyone out... just stay comfortable year round


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## GettingBy (Aug 19, 2010)

SummitRemodel said:


> If the outside is low 30's it will get me to 65. Anything below that and it stays in the 50's. But again...not needing it to smoke anyone out... just stay comfortable year round


Good.
So roughly 6 W or 20 BTU/hr per sq. ft. for a 30 F rise for average insulation. This gives me some idea of how much slop there is in the 10 W, 34 BTU/hr number.


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## SummitRemodel (Mar 18, 2009)

I havent seen his electric bill nor do I know how often it cycles on and off but it seemed efficient enough while I was there. I didn't want to go gas either.


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## GettingBy (Aug 19, 2010)

St. Cloud, Minnesota had 1600 heating degree days for last December so the avg. Dec. temp was +13 F. 
A 5 kw heater in an 800 sq. ft. garage would be able to give you +43 F. For 65 F you'd need 9 kw or more.


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## Inner10 (Mar 12, 2009)

480sparky said:


> When it comes to electric heaters, there's no difference in efficiency like there is with gas furnaces. All electric heat is 100% efficient. Every watt consumed is converted to heat. A 1000w heater that costs $100 will cost the same to run as a 1000w heater that costs $500.
> 
> So it's a matter of control, aesthetics and cost.


This is a killer for me, I don't know how many times I've tried to explain this to people and they refuse to believe it. It doesn't matter if the heater is filled with snake oil or uses laminated carp skin fan blades efficiency is not effected.


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## nailkiller1 (Jan 15, 2009)

sooooo
If their garage is 30x30 with 12 foot cielings 
insulated

Do I want the 5000 watt 17065 btu hr

Or the 7500 watt 25590 btu hr


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## Electric_Light (Nov 25, 2007)

Have you considered mini-split heatpump? If it's got an exterior facing wall, it's not all that hard to add the outside unit, and you will have cooling if needed. These have 200-400% relative efficiency, so you will use 1/2 to 1/4 the electricity (depending on how cold it is outside) compared to resistive heater. The >100% efficiency is possible, because the heat is "pumped in" by cooling the outside.

St. Paul is fairly cold, so to get the BTU output you need, you may need to oversize it, but unlike traditional HVAC system, minisplits are usually have VSD controlled compressors, so it will modulate down heating/cooling output as needed. They should have no problem maintaining average COP >1.0 as low as 0F and resistive backup should only be used when COP falls below 1.0


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