# NO HEATER at all yet; Tiny Log Cabin.. the options are?



## coachgeo (Oct 5, 2013)

This is a tiny log cabin with 12x16 foot of total space.  4" thick logs so it should have a nice R value total.   It was built to be moved by truck so it is on 1/2 a mobile  home chassis.  The plastic lining and insulation below the floor needs redoing so that opens the option of Radiant floor heat while under there anyway.

For a long time it will be a micro home rental for college student? orr?

sooooooo....... what is best bang for the buck in that case?

Small LP wall unit?

Faux LP fire place?

Radiant Floor? (CNC or LP) 

Baseboard electric

Electric Radiant heater?

orrrr?


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## Blue Jay (Oct 6, 2013)

First off logs do NOT have an R value but are classed as thermal mass, with only a 4" log it won't be much. In floor radiant would heat thru out but recovery time would be a lot longer than a flame of some kind.

I live in a log home 1500 sq ft. and use a heat pump with propane backup.


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## coachgeo (Oct 6, 2013)

Blue Jay said:


> First off logs do NOT have an R value but are classed as thermal mass, with only a 4" log it won't be much. In floor radiant would heat thru out but recovery time would be a lot longer than a flame of some kind.
> 
> I live in a log home 1500 sq ft. and use a heat pump with propane backup.


 Thanks for the info.  Good point on the thermal mass.  A radiant heater of some type might be good on top of an LP type as a fill in to get that mass warmed to help maintain the heat more efficiently.


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## iloveremodeling (Nov 22, 2013)

It might be worth asking an HVAC professional to see if they have any helpful suggestions. Good luck!


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## Wuzzat? (Dec 13, 2013)

Not a pro, but. . .

"Canadian Wood Council has a Technical Bulletin on Thermal performance of light-frame wood assemblies. It discusses an R value of 1.5/inch of thickness for wood products:&#8232;http://www.cwc.ca&#8232;&#8232;

Also, from 1993 ASHRAE standard, the R value per inch of thickness is about 1.1 F*ft^2*h/BTU per inch of thickness."


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## coachgeo (Dec 13, 2013)

Wuzzat? said:


> Not a pro, but. . .
> 
> "Canadian Wood Council has a Technical Bulletin on Thermal performance of light-frame wood assemblies. It discusses an R value of 1.5/inch of thickness for wood products:&#8232;http://www.cwc.ca&#8232;&#8232;
> 
> Also, from 1993 ASHRAE standard, the R value per inch of thickness is about 1.1 F*ft^2*h/BTU per inch of thickness."


hmmm...... now wuzaat the "F" and "h" in the last formula


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## Wuzzat? (Dec 13, 2013)

"R-values are given in units of (ft^2)·°F·hr/Btu."

12x16 is 192 Ft^2
The Grainger catalog gives rules of thumb for sizing heaters.  
Figure that 10w/(ft^2) gives you a ~100% efficient 2 kw elec. heater that you should rent.
On a cold night run the heater until the inside temp stabilizes at a comfortable level.
Then run the heater for two hours or so while the outside temp stays constant and record the kwh used on your elec. meter.
A BTU/hr is 0.293 watt.

If the outside temp is your average winter temp then this is how many BTU/hr or kw you need to heat your place and it will do the job half the time.
If you can find the outside design temperature for your location a larger heater size can be figured so it does the job 95% or 99% of the time.

Then whatever fuel or electricity gives you the least $/BTU is a good choice but you have to figure in the reduced efficiency of these other heat sources to size the heater needed.


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## coachgeo (Dec 13, 2013)

Wuzzat? said:


> "R-values are given in units of (ft^2)·°F·hr/Btu."


 Learn something new everyday

Thanks


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## Wuzzat? (Dec 14, 2013)

coachgeo said:


> Learn something new everyday
> 
> Thanks


[stuff learned each day] - [stuff you've forgotten] > 0?
:beer:


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## Countryboy26047 (Dec 14, 2013)

Just an idea here.. my initial thoughts when reading this, were the idea of installing an LP furnace that are built for pop-up campers.. They operate off of a 20lb or bigger lp cylinder which makes transporting the building with heater about as simple as could be, are thermostatically controlled, and IMO a very safe option for open-flame type heating as they are built to be used in what is basically an aluminum shell with many yds. of canvas on them..


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## Wuzzat? (Dec 14, 2013)

20 lb of LP gives about 400,000 BTU of energy.  What's this fuel cost?  How efficient are these LP heaters?

How much for 120 kwh of elec. energy in your area?  Here it's about $18.


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## Countryboy26047 (Dec 15, 2013)

Refill around here on 20lb LP is around $17-20 depending on where you go.. not sure about efficiency ratings on them to be honest though. I use one of these in a shed I have on my property, but never really paid much attention to efficiency on it as I only keep the t-stat set around 45*F because I store my diesel tractor in it along with a few other things. I was thinking more along the lines of the portability factor. Granted if the OP is going to basically set it and leave it electric would be fine, but if it get's transported a lot to different area's, you may not always have immediate or feasible access to electric.


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## inspectorD (Dec 15, 2013)

The propane is the way to go if your looking for quick heat, and have really cold outside temps. The drawback is gettin the propane filled and you still need some sort of electric ac/dc for a fan to push the air.
Another easy way is to look into the RV A/C heat pumps that run on just electricity. Simple to maintain, and you get a/c. Drawback is they don't heat fast, and don't heat in anything below about 20 degrees, depending on the unit.
This is only a 200 sq ft unit...tiny for any heat you really need, and not worth radiant $$.
Hope this helps.:help:
http://www.ebay.com/sch/sis.html?_kw=RV+Air+Conditioner+Heat+Pump+15+000+BTU+Duo+Therm


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## Wuzzat? (Dec 15, 2013)

An average US house takes 6 BTU/(Heating Degree Days x sf) so for CINCINNATI/NORTHERN KY INTERNATIONAL, KY, US (84.67W,39.04N) having 952 HDD for January, this gives you 6 x 952 x 192 = ~ 1 million BTU.  At $18 for 400,000 BTU/120 kwh this would be $49 for January.

A tight house might only cost $20.

Ya' oughta' run some tests or get the Manual J calculator off the Web or ask the log cabin people for their guesstimate.

http://www.degreedays.net/


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