Forced air furnace in fish house

[Big Dave2]

I've got a 6.5' x 12' wheel house that I built about 10-12 years ago and I want to re-do the inside before next year's ice season. I'm thinking about replacing the un-vented heater I have in there now for a vented forced air RV furnace but I have a few questions.

 

What size furnace do I need? 

How long will the furnace last on a deep cell battery when I don't want to run a generator? 

Any other type of vented heater I should consider?

[Hawg]

If you go with a wall mount you don’t have to worry about electricity, and you can install the fan kit on it when you do have electricity. I would go at least 20,000 BTU, insulation In those days isn’t what it is today. Plus no furnace is 100% efficient.

[rl_sd]

My house is a 6.5 x 14 plus v. I have a suburban Nt-20SEQ. It is not ducted, although they do make a a ducted model. It heats my house up really quick, but I also have spray foam from top to bottom. Depending on how you insulated it, you may be able to get by with a 16k BTU, but it draws the same amps as the 19k. Going the none ducted model saves you 0.4 amps.

https://www.airxcel.com/suburban/products/furnaces/ntq-p-series/ntq-series-medium-rvs

 

Back to your question though..... How many AmpHour is your battery? As a starting point, I suggest that you assume that your furnace is going to be running 40% of the time. It is all dependent on how well you are insulated, but it is a starting point. Usually for a 12v Deep Cell battery, only 50% of the AH is usable... So if you had a battery with 100 AH, you have 50 usable. If the furnace draws 2.7 amps and runs 40% of the time that means that you are using 1.08 amps every hour - meaning that you should be able to run about 50 hrs on a battery.

 

I have used both types. Here are some of the pros and cons of each type...

 

Direct Vent Wall Furnace (aka Empire)

Pros

• No battery usage
• Quiet heat

Cons

• Takes up more room (both inside and outside of the house)
• Not very even heat (the guy sitting next to the heater always bakes...)
• More expensive than a fan forced

 

Power vent fan-forced Furnace (aka Suburban)

Pros

• Heats quickly and evenly
• Keeps floor warmer due to fan
• Can be configured in a small space

Cons

• Noisier than a wall unit (although the new suburban models with the "q" in the name draw less juice and are a lot quieter)
• Requires power to run

[Lip_Ripper Guy]

These guys pretty much covered it.  The Suburban NT20SQ is a good unit, and is nice and quiet, without drawing a ton of power.  If you are needing batteries soon, I'd highly suggest picking up the (2) GC2 6 volt golf cart batteries from Sam's Club for around $85/each.  That'll get you 230 amp hours, so you can run an easy 3-4 day weekend without drawing down your batteries too much.  

 

Plan your cabinet to have adequate return air venting, and clearance around the furnace and vents.  Acoustic foam makes a huge difference in terms of noise.     

[Fathom]

Do those batteries need to be vented? And would you run them in series or parallel?

[rl_sd]

They would be ran in series in order to get 12 vdc. Yes, they need to be vented.

[Snowbound]

I built a 6 x 10 skid house and have no problem heating with a Suburban 16K forced air heater.

I run it off a 100ah 31 series battery from my boat.

I charge it with a Renogy 100w solar panel

 

Nice system, works well

[Big Dave2]

9 hours ago, Hawg said:

If you go with a wall mount you don’t have to worry about electricity, and you can install the fan kit on it when you do have electricity. I would go at least 20,000 BTU, insulation In those days isn’t what it is today. Plus no furnace is 100% efficient.

 

Are you talking about an Empire or something else? 

Is it possible to have a wall hanging vented heater with a blower that you don't have to run if you are low on battery power? That may be ideal if it exists. 

 

Edited January 23, 2018 by Big Dave2

[rl_sd]

22 minutes ago, Big Dave2 said:

 

Are you talking about an Empire or something else? 

Is it possible to have a wall hanging vented heater with a blower that you don't have to run if you are low on battery power? That may be ideal if it exists. 

 

 

As far as the blower goes.. I don't think that Empire makes a 12VDC version... maybe some of the others do?

[fishingstar]

I have a Empire that I use in a 12" homemade wheel house. They don't make a blower for 12v just 110.  I have 2 computer fans and a 12" ceiling

fan to move the air. If it is real cold out it does take some time to warm it up. I have the 15000 btu and I paid around 650 two years ago.

[BlackLabGuy]

We put a Williams 30,000 BTU Direct Vent ($663 @ Menards) heater in our OLD and not very well insulated 8x16 ice castle. It will heat it up quickly and maintain heat no prob on the coldest days. We run a Clam fan unit hanging on the ceiling and it evens things out pretty well.

[papadarv]

I have a 6.5 x 12 W/v front 3" walls floor cealing fiberglass insulation. I use a 12,000 btu vented convection heater from an old 78' P/U camper with added forced air. On Ottertail 1/11 - 15 temp at -17 to -21 wind @ 25 mph. Furnace ran for about 10 min. Than off for 15 mln. On ice from 2 pm to 11pm 4 days. Took off ice each night charged 2 parallel batteries & ran 1500 watt 110 heater keeping house warm. Burned 16# of propane over weekend. Have 2 compuuter fans & 4 speed auto fan (on low) to move air. Inside temp at 71 deg. Very even heat. Never run out of battery power. If i ever upgrade furnace i would use a 20 - 25000 BTU forced air RV furnace.

[Niteryder]

I was in the same boat.   But then I decided that I never want to rely on power.   This thing is way overkill, but no LP gas headache here.   I do have a small 12v fan on the ceiling to move air, but when the house gets to temp, it's not really needed.

 

[phild111]

On 1/23/2018 at 8:00 AM, Lip_Ripper Guy said:

These guys pretty much covered it.  The Suburban NT20SQ is a good unit, and is nice and quiet, without drawing a ton of power.  If you are needing batteries soon, I'd highly suggest picking up the (2) GC2 6 volt golf cart batteries from Sam's Club for around $85/each.  That'll get you 230 amp hours, so you can run an easy 3-4 day weekend without drawing down your batteries too much.  

 

Plan your cabinet to have adequate return air venting, and clearance around the furnace and vents.  Acoustic foam makes a huge difference in terms of noise.     

 

Where would the acoustic foam be best placed?