# Efficiency of Jensen Wood Furnace



## Tinytorpedo (Jan 22, 2018)

Wondering if anyone knows the efficiency of a Jensen indoor wood furnace like this?


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## U.P.Boiler (Jan 22, 2018)

Tinytorpedo said:


> Wondering if anyone knows the efficiency of a Jensen indoor wood furnace like this?
> 
> View attachment 221393


I had one similar.  Came with the house I bought.  It was a fire breathing dragon in the basement.  Kept the house uncomfortably hot, 25 below outside and 80 inside.  I had windows cracked open.  It was old and at the end of its usable life but for an upper peninsula winter with older windows and decent insulation in the roof area I was burning 6 to 8 cords of wood a winter.  Downfall was the mess was in the basement.   Bugs, mice, dust and dirt.  Nice thing was that I could stoke it in my tighty whities instead of going out to the boiler. 

Sent from my SM-G935V using Tapatalk


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## brenndatomu (Jan 22, 2018)

Tinytorpedo said:


> Wondering if anyone knows the efficiency of a Jensen indoor wood furnace like this?
> 
> View attachment 221393


The efficiency rating? Probably 60%...a good operator might squeak towards 70% out of it...maybe...on a good day...


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## Tinytorpedo (Jan 23, 2018)

U.P.Boiler said:


> I had one similar.  Came with the house I bought.  It was a fire breathing dragon in the basement.  Kept the house uncomfortably hot, 25 below outside and 80 inside.  I had windows cracked open.  It was old and at the end of its usable life but for an upper peninsula winter with older windows and decent insulation in the roof area I was burning 6 to 8 cords of wood a winter.  Downfall was the mess was in the basement.   Bugs, mice, dust and dirt.  Nice thing was that I could stoke it in my tighty whities instead of going out to the boiler.
> 
> Sent from my SM-G935V using Tapatalk


Thanks for the reply.  About how many SF was your home?


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## Tinytorpedo (Jan 23, 2018)

brenndatomu said:


> The efficiency rating? Probably 60%...a good operator might squeak towards 70% out of it...maybe...on a good day...


60% ?, that is what I was afraid of.  Thanks.


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## maple1 (Jan 23, 2018)

I am thinking 60% could be an optimistic estimate. There are all kinds of variables though.

My number guess is, 'not very'.


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## U.P.Boiler (Jan 23, 2018)

Tinytorpedo said:


> Thanks for the reply.  About how many SF was your home?


I have a 2300 as ft of actual heated space.    The best thing you can do is seal your house up.  Windows and door seals.  Check being door and window moulding. Replace old windows if needed.   Make sure you have adequate ventilation in the attic areas.  Once that is done you will be surprised that you won't want to fill that fire breathing dragon as much.  

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## laynes69 (Jan 23, 2018)

I was thinking in the 40% range, considering high stack temps and creosote. Epa tests default at 60%.


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## Tinytorpedo (Mar 13, 2019)

maple1 said:


> I am thinking 60% could be an optimistic estimate. There are all kinds of variables though.
> 
> My number guess is, 'not very'.


I was told by the company that bought out Jensen that the efficiency was 73%.


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## JRHAWK9 (Mar 13, 2019)

Tinytorpedo said:


> I was told by the company that bought out Jensen that the efficiency was 73%.


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## Tinytorpedo (Mar 14, 2019)

JRHAWK9 said:


>


I was not disagreeing with the previous input, just wanted to share what the manufacturer had to say about efficiency.  Thanks much for your comment.


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## TCaldwell (Mar 14, 2019)

What’s your flue temp with this unit


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## Tinytorpedo (Mar 14, 2019)

TCaldwell said:


> What’s your flue temp with this unit


This furnace is in a retirement home I purchased and we have not moved into it yet.  We will be moving there soon.  What flue temperature should I be expecting?


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## 3fordasho (Mar 14, 2019)

Tinytorpedo said:


> This furnace is in a retirement home I purchased and we have not moved into it yet.  We will be moving there soon.  What flue temperature should I be expecting?



Not sure what you will see with the Jensen, but a EPA rated furnace like one of my Drolet Tundra's will see 350-400F flue temps during the active part of the burn - meaning good active flames and secondary flame action.  I get some variation due to draft differences due to lack of a barometric damper.  On a cold and very windy day, my temps will run higher but again this is due to the draft being on the high side.  Also this is with wood with  an actual moisture content at 20% or a touch less.

My EPA rated free standing stove, a 30NC can see 600-700F flue temp during the same part of the burn, a clean burner as well but due to no heat exchanger it's allowing more heat up the flue so efficiency takes a hit.


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## JRHAWK9 (Mar 14, 2019)

Tinytorpedo said:


> I was not disagreeing with the previous input, just wanted to share what the manufacturer had to say about efficiency.  Thanks much for your comment.



sorry, I can be a sarcastic a$$hole at times.  

This is my life's moto.    




Seriously though.  Don't believe anything manufacturers tell you unless you see the test report for yourself or they are citing the CSA B415.1–10 testing procedure.  Even then you have to make sure you are looking at the correct efficiency number.  Input and burning efficiencies are useless.  Stack loss efficiency, delivered efficiency and LHV are the ones to look at.  Stack loss being the most accurate measure of heat NOT lost solely up the chimney.


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## Tinytorpedo (Mar 14, 2019)

3fordasho said:


> Not sure what you will see with the Jensen, but a EPA rated furnace like one of my Drolet Tundra's will see 350-400F flue temps during the active part of the burn - meaning good active flames and secondary flame action.  I get some variation due to draft differences due to lack of a barometric damper.  On a cold and very windy day, my temps will run higher but again this is due to the draft being on the high side.  Also this is with wood with  an actual moisture content at 20% or a touch less.
> 
> My EPA rated free standing stove, a 30NC can see 600-700F flue temp during the same part of the burn, a clean burner as well but due to no heat exchanger it's allowing more heat up the flue so efficiency takes a hit.



Thanks.


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