How would you heat this house and shop?

[PNWguy]

I have to admit that I'm a little overwhelmed by the options for boilers and systems.
Euro import vs US made, storage vs no storage, pressurized vs not...
I'm hoping to get some feedback.

This ended up being kind of long, but I'm trying to include as many details as possible.

I am building a 800 sq ft (not a typo) house with a 1 car garage and a big shop (can you guess how many wives and kids I have?)
The land is in southwestern Oregon, just outside of Grants Pass. Winter weather is cold, but not by midwest/northeast standards. We generally get down into the 20's & 30's (F) for a month or so. My family and friends heat with traditional wood stoves. They usually start a fire in September or October and it burns till March. Burning 6-8 cords a season seems about normal.

The wood on the property (I have 10 acres, but can cut on my parents' 50 acre place next door) is 80/20 pine/hardwood. We cut wood, and let it dry in piles outdoors till fall, then put it in the wood shed.

The house & shop will be new construction, and well insulated.

House
The first floor will be a 500-600' "great room" (kitchen/dining/living) and a 1/2 bath. It'll be either concrete or hardwood floors - with radiant floor heating. The upstairs bedroom will cover half the great room and part of the garage. It'll have radiant heat under the hardwood floors.

The garage will hold my truck, and will have concrete with radiant heat (kept at 50 degrees or so).

Shop
1,600 - 1,800 sq ft, with a few different rooms. Concrete floor, with radiant heat.
I'm thinking of heating the shop to 50 or so, and heating up the area I'm working in with forced air (possibly a car radiator and big fan).

Wood shed/boiler room
I want the wood shed & boiler to be between the house & shop, about 20 or 30 feet from the house and 100 feet from the shop.

Storage
Because the house is so small, it seems that a large storage tank would be a good thing. I'm thinking that a big fire and 500 or so gallons of hot water should keep me warm all day & night, unless it's really cold out.

Potential problems & Questions
I want the water storage to be in the shop, but don't want to pay for 200 feet of Pex Flex to run from the boiler, to the shop to the house and back to the boiler.
Does it make sense to have storage in the garage and in the shop? Obviously, there would need to be some work to balance them so that they request more hot water at roughly the same time.

Heating the upstairs bedroom. I assume that the upstairs will be warmer than the downstairs, because heat rises. I'm wondering if I'll even need heat upstairs. I assume I can have a zone for downstairs, upstairs, the garage and the shop.

Equipment
The west coast is slim on dealers for OWBs. I found a nearby dealer for Central Boilers, but everything else (that I have found, so far) is 500+ miles away.

I know this is a ton of questions, but I'm curious to hear what some of you would do in this situation.

Thanks in advance

 

[PassionForFire&Water]

In my opinion, any new house designed and build today, new from the ground up, hould not need much of a heating system
The technology and building materials are there to build a very well insulated house with the required ventilation.

Look into passive solar, passive house concepts
without to much technicalities you should be able to build within budget for a design load of 10 BTU/sf
In your case 800 x 10 = 8,000 BTU/hr

Also, where you gone put the wood boiler and thermal storage tank if you only have 800 SF available

A very small wood stove will serve you best; but to oversize

 

[jebatty]

Interesting and exciting. Your questions are appropriate but premature. A lot more information is needed before I would be in a position to offer sound advice.

I would start with the building design, air sealing, air exchange and insulation specifications, and from this determining the heat loss in your heated spaces based on heating degree day data for your area. Design would include taking advantage of passive solar opportunities and possibly active solar potential, both for space heating and for electricity. With this information you can determine the btuh heating requirements for each space, and that gives a basis to start looking at heating equipment options: hot water wood boiler, free-standing wood stove, mini-split heat pump(s), forced air wood furnace, etc.

Family and friends burning 6-8 cords/season seems like a lot for me, but I don't know what spaces they are heating. I live in a much colder climate. We just finished a two week stretch with lows into the -30F range, and now starting another stretch with lows into the -20F range. And we only burn about 4 cords/season of mostly aspen for a 1500 sq ft house main level, plus 1500 sq ft walkout lower level, and this is for a house built in 1956 with window and insulation upgrades.

If you are set on a wood burning heat source, then I also would start accumulating a cut, split and stacked wood supply to meet heating needs for two heating seasons, and then replenishing so that you start each heating season with two years supply on hand. Well seasoned wood of appropriate split size is critical for efficient operation of any wood heating source. Poorly seasoned/sized wood can be a recipe for a poor performing, polluting, and potentially dangerous wood heating system.

Wishing you home building turns out to meet all of your expectations.

 

[maple1]

I would make the shop big enough to hold the boiler and entire winters wood and storage (1000 gallons). That could be an indoor boiler. Partition that part off from the rest, if you need to or it would be an insurance issue. Do away with the building in between. Run 120' of thermopex from the shop to the house.

Ductless heat pumps for backup or when you might be away in winter. And summer A/C.

 

[PNWguy]

I would start with the building design, air sealing, air exchange and insulation specifications, and from this determining the heat loss in your heated spaces based on heating degree day data for your area. Design would include taking advantage of passive solar opportunities and possibly active solar potential, both for space heating and for electricity. With this information you can determine the btuh heating requirements for each space, and that gives a basis to start looking at heating equipment options: hot water wood boiler, free-standing wood stove, mini-split heat pump(s), forced air wood furnace, etc.

I'm looking into solar, but I think the payback would be too long to make it worthwhile. My electric load will be minimal - LED lighting, LPG appliances, and not much in terms of electricity use. Remember this is for one person - one room with lights on, one person showering, one person doing laundry... Our power is fairly cheap here as well.

Family and friends burning 6-8 cords/season seems like a lot for me, but I don't know what spaces they are heating. I live in a much colder climate. We just finished a two week stretch with lows into the -30F range, and now starting another stretch with lows into the -20F range. And we only burn about 4 cords/season of mostly aspen for a 1500 sq ft house main level, plus 1500 sq ft walkout lower level, and this is for a house built in 1956 with window and insulation upgrades.

The folks I'm referring to heat with traditional wood stoves, in older houses and don't use another heat source.
If you're heating your house with a wood stove, I'm really impressed by your wood use. If you're using a OWB, then these may be even more efficient than I was thinking.

If you are set on a wood burning heat source, then I also would start accumulating a cut, split and stacked wood supply to meet heating needs for two heating seasons, and then replenishing so that you start each heating season with two years supply on hand. Well seasoned wood of appropriate split size is critical for efficient operation of any wood heating source. Poorly seasoned/sized wood can be a recipe for a poor performing, polluting, and potentially dangerous wood heating system.

I grew up here, and have been cutting, splitting, stacking and burning wood since '72. I have access to the equipment that makes firewood collection "easy" (tractor, excavator, hydraulic splitter, etc.)

As an aside... our method of getting wood is to drive an excavator into the woods, towing a 12' x 4' trailer. We cut the tree, trim the branches (which go through the PTO mounted chipper on a tractor) and cut the logs to 12'. Pick up the logs with the excavator and place them on the trailer. Repeat till the trailer is full. We drive the excavator & trailer close to the house, on an old road bed (it's hard packed gravel with a bed of chips). The trailer is built to hold logs while they are being cut to length, and because it's 4' wide, we can cut all the logs to length at once by cutting from both sides. Small logs get pushed off the trailer, and larger ones go on the splitter. Huge ones get picked up with the excavator and set on the splitter. When the pile of firewood is 3' or 4' high, we move forward a bit and continue to cut & split. What we end up with is a very long, 8' wide, 4' high row of cut, split logs. They bake in the sun all summer and dry out. The row is kept short so that everything is nice and dry. I haven't checked with a moisture meter, but it's dry. As a kid, we occasionally got behind schedule for cutting (before we had the extra equipment, and cut and split everything by hand) and I know what a pain burning green wood is.

Thanks for your info. As the house design gets closer, I'l do some sort of energy audit and have a better handle on my needs.

 

[PNWguy]

I would make the shop big enough to hold the boiler and entire winters wood and storage (1000 gallons). That could be an indoor boiler. Partition that part off from the rest, if you need to or it would be an insurance issue. Do away with the building in between. Run 120' of thermopex from the shop to the house.

Ductless heat pumps for backup or when you might be away in winter. And summer A/C.

I though of putting the boiler into the shop, but don't want to bring any bugs into the building. I'm in favor of keeping the wood close to, but separated from the house. I'm planning to enclose the wood shed, so I can use an indoor boiler.

 

[maple1]

I would still likely put the boiler & storage in the shop or one end of it, even if you wanted to park the wood outside. At least then the standby heat will be usable by the shop, and you will eliminate a structure. And maybe simplify your underground piping.

 

[Golovkin]

Does the shop really need to be 100' from the house? Also, heat doesn't rise, hot air rises. the upstairs of a radiant floor heated house doesn't pick up as much hot air as you might anticipate. Also, *and this is important* - design your radiant heating with many short zones, and put runs on close centers to maximize storage. Storage depends on a system that can operate at low temps.. You start at say 200F , you want that storage to still heat when the tank gets down to 90F. Skimp on the zones, aluminum plate, or spacing and you have a system that requires high heat and your storage doesn't go very far.

 

[vtwoodheater]

Are you going to insulate with closed cell spray foam? (Being a new build and all)

 

[PNWguy]

Does the shop really need to be 100' from the house? Also, heat doesn't rise, hot air rises. the upstairs of a radiant floor heated house doesn't pick up as much hot air as you might anticipate. Also, *and this is important* - design your radiant heating with many short zones, and put runs on close centers to maximize storage. Storage depends on a system that can operate at low temps.. You start at say 200F , you want that storage to still heat when the tank gets down to 90F. Skimp on the zones, aluminum plate, or spacing and you have a system that requires high heat and your storage doesn't go very far.

I plan to move the shop away from the house, just so that the shop doesn't dwarf the house. It's just for aesthetics, and it's not final yet.

The piece of land is stunningly beautiful, and I want the structures to look good (not fancy or ultra-modern) by fitting in with the forest & meadow I'll be building them in. It may end up being 50' or 75' or 125'. Obviously closer is more convenient, and further away is (probably) more attractive.

 

[surefire]

As an aside... our method of getting wood is to drive an excavator into the woods, towing a 12' x 4' trailer. We cut the tree, trim the branches (which go through the PTO mounted chipper on a tractor) and cut the logs to 12'. Pick up the logs with the excavator and place them on the trailer. Repeat till the trailer is full. We drive the excavator & trailer close to the house, on an old road bed (it's hard packed gravel with a bed of chips). The trailer is built to hold logs while they are being cut to length, and because it's 4' wide, we can cut all the logs to length at once by cutting from both sides. Small logs get pushed off the trailer, and larger ones go on the splitter. Huge ones get picked up with the excavator and set on the splitter. When the pile of firewood is 3' or 4' high, we move forward a bit and continue to cut & split. What we end up with is a very long, 8' wide, 4' high row of cut, split logs. They bake in the sun all summer and dry out. The row is kept short so that everything is nice and dry. I haven't checked with a moisture meter, but it's dry.

Would you post some photos of your processing setup? I'd like to see that.

 

[PNWguy]

Would you post some photos of your processing setup? I'd like to see that.

As soon as we get the water pump in the excavator fixed, we'll start cutting wood for the year. I'll post some photos when we get started.

 

[rowerwet]

You might look into a propane floor furnace for backup heat for the house. They require no power, as long as the tank is full, you have heat

 

[maple1]

I just re-read the OP. That is not a lot of space, if I read right (like, 2500 sq.ft. total?), of new construction (potential for very low heat load), and not a very cold climate.

I think I would be tempted to just put in a couple of mini-splits & be done with it. That won't get you radiant floors, but if you insulate well under them, they shouldn't be that cold feeling. Then if you want you could supplement with wood in either place - a stove for the house, furnace for the shop?

 

[PNWguy]

You might look into a propane floor furnace for backup heat for the house. They require no power, as long as the tank is full, you have heat

I'm going for electric backup. It should keep the plants & pets from freezing when I'm away, and with a solar PV system, should be expensive to run.

 

[PNWguy]

I just re-read the OP. That is not a lot of space, if I read right (like, 2500 sq.ft. total?), of new construction (potential for very low heat load), and not a very cold climate.

I think I would be tempted to just put in a couple of mini-splits & be done with it. That won't get you radiant floors, but if you insulate well under them, they shouldn't be that cold feeling. Then if you want you could supplement with wood in either place - a stove for the house, furnace for the shop?

I've expanded the house and shop a bit, and it's closer to 3,000 now.
My goal is to have constant heat in the shop (and of course the house) without burning wood inside the house.

I can't use a wood stove to heat the shop. Some insurance companies around here won't insure a garage/shop with wood heat, and I don't want open flame in the shop. Propane is expensive and using it to keep my shop at 55 all winter would be hundreds of dollars a month. I don't want forced air in the shop, because it blows dust around as well.

I really think that a wood boiler is the best option for my situation. Well, I hope it is. It should be a good heat source at a decent price.

 

[maple1]

Ok. Back to my post #4 then.

 

[Chris Hoskin]

Hi, PNWguy, based on the size of the house, I wouldn't go too crazy on the type of construction and/or insulation. You live in a moderate climate and with decent, modern construction and windows, your heating load is not likely to exceed 20 btu/square foot. Remember too that that 16,000 to 20,000 btu/hour heating load is on the coldest day of the year. Your biggest problem is going to be finding a heating system SMALL enough. A small, single mini-split might do it, but a woodstove is going to be too big and will either over-heat the house or smolder all the time (likely both).

As you might expect, I love the idea of having the wood boiler and thermal storage in the shop. In fact, I would put your back-up boiler down there too. Run supply/return lines to a buffer tank/indirect water heater in the house and pull off for your zones there. Anytime the buffer tank drops below usable temp (120F, let's say), the pump from the shop would turn on and bring the buffer tank back up to temp. Your radiant floor zones are never going to need water as warm as 120 in the house you describe, but you won't want to drop much lower than that so you can still make domestic hot water. Cool project, keep us posted.

 

[PNWguy]

Hi, PNWguy, based on the size of the house, I wouldn't go too crazy on the type of construction and/or insulation. You live in a moderate climate and with decent, modern construction and windows, your heating load is not likely to exceed 20 btu/square foot. Remember too that that 16,000 to 20,000 btu/hour heating load is on the coldest day of the year. Your biggest problem is going to be finding a heating system SMALL enough. A small, single mini-split might do it, but a woodstove is going to be too big and will either over-heat the house or smolder all the time (likely both).

As you might expect, I love the idea of having the wood boiler and thermal storage in the shop. In fact, I would put your back-up boiler down there too. Run supply/return lines to a buffer tank/indirect water heater in the house and pull off for your zones there. Anytime the buffer tank drops below usable temp (120F, let's say), the pump from the shop would turn on and bring the buffer tank back up to temp. Your radiant floor zones are never going to need water as warm as 120 in the house you describe, but you won't want to drop much lower than that so you can still make domestic hot water. Cool project, keep us posted.

I'm definitely not going for a wood stove.
The state requires "better than code" for some parts of the construction, and my options are pretty much limited to R28 in the walls of the house. I'll probably have to use 8" studs (they don't count 2x6 with 1" of closed cell expanding foam, plus BiB as R28). But hey, it'll be quiet and cozy. One extremely stupid possibility is that I'll have to put in electric baseboards to pass inspection - it depends on how my county interprets one of the rules.

In all honesty, the reason to go with a boiler is to keep the shop warm, as I'll be able to heat the house by turning on the coffee pot or making toast. I hate the shop I'm in now, as it never seems to be above 40 in there, unless we build a fire. The slab never warms up, and it's really tiring to stand on cold concrete for more than a little while.

I've decided to attach the house to the shop, and both spaces have grown a bit. The house is now 700 downstairs/300 upstairs and the shop is 2000 downstairs/400 upstairs. There will be 2,700 sq ft of slab, and 1,100 of something else.

The boiler room, woodshed and water storage (1,000 gallons?) will be 20' from the house, to keep the insurance folks happy.