New house, need advise on wood furnace

[jhorst14]

My wife and I are building a new house here in MD. We are planning to install a wood furnace in the basement which will be connected to the ducts for the propane furnace. I plan to use the wood furnace quite a bit (I have a ton of firewood and 27 acres of mature woods to cut for the future). We are also putting a wood stove on the first floor.

I have been looking at furnaces and wanted some recommendations. I really like the Kuuma Vapor Fire 100, but its quite pricey. Just wondering if the price is worth it? It boasts some cool features.

We are also looking at some more cost efficient models like the Woodchuck Model 400. I like that they have the water heater option on this one. That would be nice option to have as well.

The house will be ~ 3,450 ft^2 when finished.

Any recommendations/advise?

 

[maple1]

I'm quite sure the Kuuma also has a water heating option.

If you are set on a wood furnace that you will use a long time, the Kuuma would be my first consideration.

 

[brenndatomu]

We are also looking at some more cost efficient models like the Woodchuck Model 400.

Not familiar, is that a wood/coal furnace? If so, RUN!
IMO you can't get a decent wood furnace under $2k barring going used or finding a great sale.
The Drolet Heatpro or PSG Caddy would serve that size house with no problems...

 

[3fordasho]

Not familiar, is that a wood/coal furnace? If so, RUN!
IMO you can't get a decent wood furnace under $2k barring going used or finding a great sale.
The Drolet Heatpro or PSG MAX Caddy would serve that size house with no problems...

Fixed that for ya

 

[Highbeam]

3500 SF (plus sometimes you east coasters forget to include the basement area) is likely beyond the capabilities of the biggest Kuuma. Call them up, they will talk to you, this is a BIG purchase. The kuuma has no window but has very low emissions. The efficiency is pretty good too.

The sweet spot in value seems to be the caddy line.

 

[JRHAWK9]

The VF100 also has an option for a water coil to pre-heat your DHW. This is what I'm doing by pre-heating 30 gallons using a tempering tank which then feeds my water heater. For ease of operation, very efficient CLEAN burns and a true "load and go" system right out of the box.....Kuuma hands down. See attached comparison.

You have a rather large house, but with having a stove on the first floor to use during the shoulder seasons and during those real cold nights, you will be fine. You do realize you will need two separate flues for both wood appliances, correct?

 

[jhorst14]

The VF100 also has an option for a water coil to pre-heat your DHW. This is what I'm doing by pre-heating 30 gallons using a tempering tank which then feeds my water heater. For ease of operation, very efficient CLEAN burns and a true "load and go" system right out of the box.....Kuuma hands down. See attached comparison.

You have a rather large house, but with having a stove on the first floor to use during the shoulder seasons and during those real cold nights, you will be fine. You do realize you will need two separate flues for both wood appliances, correct?

yup, we will have 2 flues. The house has propane primary, but I am hoping to use this furnace as much as possible to avoid buying much propane.

 

[laynes69]

Does the square footage include the basement? There's others currently in the market, the HMF line from Napoleon, Firecheif, Shelter and also the golden eagle by Usstove. I looked at the Golden eagle 7700 in person, and they are well built and also made in the US.

 

[jhorst14]

this doesn't include the basement which is unfinished.

 

[JRHAWK9]

yup, we will have 2 flues. The house has propane primary, but I am hoping to use this furnace as much as possible to avoid buying much propane.

We have a log cabin style (open concept, with loft and ~30' ceilings and no attic) with a 32'x42' footprint. Definitely not a very efficient design. Heat load calc states it to be between 55,000 - 65,000 BTU's/HR at 0° outside keeping it 70° inside. Heating the whole place (including basement) is equivalent to a ~3,300 SF house. I think last winter 98+% of my BTU's came from wood when we were home. I will look at my spreadsheet when I get home. LP thermostat set to 68°, so LP would kick in if it dropped below 68°.

EDIT:
Here's last heating season's results. 99.6% wood heat when home and 94.6% in total (includes the times we were gone and unable to load wood furnace).

 

[maple1]

3500 SF (plus sometimes you east coasters forget to include the basement area) is likely beyond the capabilities of the biggest Kuuma. Call them up, they will talk to you, this is a BIG purchase. The kuuma has no window but has very low emissions. The efficiency is pretty good too.

The sweet spot in value seems to be the caddy line.

I don't think it would be beyond its capabilities. New construction, in Maryland, shouldn't be an overly big heat load even with 3000+ sq.ft., as long as the construction is done as well as it should be. Plus maybe with some thought to southern exposure. Modern techniques & materials have come a long ways.

 

[Wood1Dennis]

You sound like me two years ago when I was stockpiling firewood and researching all the wood heating options I could find for our new home! We are going into season #2 in our new house with a Caddy furnace set up just like you are describing. It is in series with, downstream from the LP forced air furnace using the LP furnace fan. I love the set-up. The Caddy is perfectly sized for our 1700 square foot efficient ranch home. For your place at double the size I expect you would need the Max Caddy. Make sure to plan a wood chute to get the firewood down to the basement.

The Caddy may not be able tout the ultra low emision of the Kuuma, but it burns very clean and efficiently. It really takes no time to get it going and for the secondaries to kick in. At that point there is next to no smoke. When I bought ours Caddy did not offer a hot water heat option. It is a small thing, but I would really miss the glass door, I love to sit down there and watch the fire.

I looked at the Kuuma, but for the price of the furnace alone, I got a turnkey system, the Caddy installed, chimney and all from a local contractor. I just could not justify the cost difference.

Good luck!

 

[motoguy]

3500 SF (plus sometimes you east coasters forget to include the basement area) is likely beyond the capabilities of the biggest Kuuma. Call them up, they will talk to you, this is a BIG purchase. The kuuma has no window but has very low emissions. The efficiency is pretty good too.

The sweet spot in value seems to be the caddy line.

Our house is ~4k sq/ft. We have tall (10ft) ceilings in the basement, and tall vaulted ceilings upstairs. While our sq/footage is a little beyond the stated Kuuma rating, I'm sure our interior volume is far beyond it's rating.

That being said, I LOVE our VF100. It's a basic install (manometer and supplied T-stat), with nothing additional done to improve efficicency (I need to do that in the future.) In fact, I'm still burning 3 year old wood that is not sized to maximize the output, either. It's short (~18"), and BIG splits (cut it before we had the Kuuma, remembering the size of the splits we used growing up, in the 'ol smoke dragon). The Kuuma can handle about a 45 degree temperature delta, all by itself. We like to keep the house at 68 inside. The Kuuma handles that fine by itself, until temps get to the low 20's or teens. At that point, the LP starts kicking in.

Last year, I read several tips and tricks that would increase the output of the Kuuma. Having the return air scavenge hot air from the face of the furnace. Relocating the plenum temp probe. Several others that I can't remember. Performing some of those mods would likely increase the temperature delta as well.

The reduction in LP usage has been dramatic. I had hoped the Kuuma would be able to heat the house by itself, and if I were to put in the time for the mods, perhaps it would. But even the ability to get the first 45 degrees of heat 'free' has made a massive difference in comfort and costs for LP.

 

[motoguy]

I'm quite sure the Kuuma also has a water heating option.

If you are set on a wood furnace that you will use a long time, the Kuuma would be my first consideration.

It does. We have the water coil/heating option for our Kuuma, but I've not installed it yet. I also have a pair of used/inop 50gal water heaters to use as storage tanks.

 

[STIHLY DAN]

My old man lives in MD. Any wood furnace would be big enough. It just doesn't get cold in MD. The Kuuma might even be to large as it can only fire so low.

 

[3fordasho]

My old man lives in MD. Any wood furnace would be big enough. It just doesn't get cold in MD. The Kuuma might even be to large as it can only fire so low.

Good catch, here we are recommending a larger wood furnace, thinking everyone lives in the frozen tundra of MN or North Dakota !