Passive House with Windhager BioWIN

Installation of a Windhager BioWIN100S in a passive house (Waldo county - Maine).
Pellets are fed manually into the 320 Lbs pellet hopper.
Less then 2 bags of wood pellets per week, and 70% of this is for heating the DHW.

SUPER

TIP: Insulate first, .... then look into a biomass appliance. Saves you $$$$ for the years to come

Wow.....Nice set-up. I noticed you have sprayed in foam insulation in the floor joists above. Why, exactly? Simply to keep colder air from your basement from somehow getting up into your first floor living space. To keep noise levels low upstairs? For both reasons?

Hi! Looks like a great project. Was that a retrofit of an existing home to passive house standards? I always wondered how difficult/expensive that would be. If you have some time and could elaborate a bit on the process I am sure many people here would be interested. Thanks!

Hi Grisu, check out this link for more information:
http://www.greenhomesofmaine.com/deep-energy-retrofit-charlottes-retro-in-northport-maine

FYI: This article dates from before the installation of the Windhager BioWIN100 pellet boiler.

Very "together" looking install. May I ask what and where the backup is?

No backup at all.

This customer was familiar with the Windhager brand of wood pellet boilers.
He took his old oil burner to the scrap yard with a big smile on his face.

I also need to say that this type of passive house retrofit does not need much of heating.
The DHW takes 70% of the pellet consumption.
The installed model is 35,000 BTU/hr (BioWIN100S).
S stands for manual fill of wood hopper (325 Lbs)

So that hopper will hold eight bags worth? I wonder how many days that would go for a newish house of 2000 ft2? Like, real cold and more normal?

To give you some first ball park number on heat loss, you can use these guidelines for "moderate" New England conditions:

- old house not insulated or poorly insulated: SF of house x 37 BTU/sf

- house in 2x4 stick construction fairly well insulated: SF of house x 30 BTU/sf

- house in 2x6 stick construction very well insulated and tight: SF of house x 25 BTU/sf

- house in 2x6 stick construction super insulated and very tight: SF of house x 15 BTU/sf

- Passive House: SF of house x 8 BTU/sf

Example:
a 2x6 stick build house in 2012 of 2,000 SF should have a max heat loss of 2,000 x 25 = 50,000 BTU/hr
The same square footage for an old house would result in 2,000SF x 37 = 74,000 BTU/hr, what is 50% more

The above guidelines include for DHW for 2 adults and 2 kids.

These guidelines are up for lots of discussions and other trade professionals will have their say on them, but it gives you a ballpark.
If you apply them you will not end up with a boiler that is way over-sized, ... or undersized.

8 bags x 40 Lbs per bag = 320 Lbs * 8,100 BTU/lb = 2,590,000 BTU's
2,560,000 BTU's / 50,000 BTU/hr = 52 hours of continuous burn, what's 2.1 days

so, on average I would say around 4 days

Thanks much.

Iv always thought you could cover the exterior of your existing home with thick foam or SIPs to get the super insulated effect. I may try this in the near future.
The next home ill be rehabbing may get 1" foam under he drywall + foam under the siding + blown in cellulose in between. Ill post he results.

At least one of those foams needs to be open cell....so you don't get the dreaded 'two vapor barrier' problem. In our mixed frigid/tropical climate zone, prob doesn't matter much which one or both.

Thats good to know. I get excellent results even with just the blown-in cellulose. IF more homes were well insulated ,all you would need is a wood stove backup.No furnace. Last house did with just the blown-in never went below 48 without heat in mid winter. Outside temps were in the 20s.

Im doing an apt building now,i may do the blown-in and foam as well. THe north side has no windows at all, so its easy to install the foam both inside and out.