Equipment

This page contains the list of equipment I hope to be using in the house.

Heating system: Pioneer Ductless Wall Mount Mini Split, one per room for 3 total. Likely getting the 120V, 12000 BTU version. Manual located at https://www.highseer.com/pdf/WYB_IM.pdf. 20 amp circuit for each.

Water heater: Stiebel Eltron ACC300 Accelera 300. 80 gallon water heater. 79 inches tall. Should be installed in attic, because it will cool and air condition the room that it’s in. Manual located at http://www.stiebel-eltron-usa.com/sites/default/files/pdf/install-accelera-300.pdf. Requires a 220v, 15 amp breaker. Must be installed in a room that is at least 800 cubic feet. (Attic will easily meet that.) At least 2 feet from the wall on the air intake side and 6 feet from the wall on the exhaust side. At least 8 inches from the wall on the non-air sides.

Bathroom fans: Delta BreezRadiance RAD80L with light and heater. 80CFM. See sizing notes at https://www.efi.org/factoids/bathroom_sizing.html. 80CFM is plenty for bathrooms of that size. Manual at http://www.deltabreez.com/Upload/SalesBinder/5_IM/5_Radiance/RAD80L_IM_e.pdf. Requires a dedicated 20 amp GFCI circuit. Should be installed within 5 feet or shower head for minimal heat loss while having maximum ventilation. Can either have a wall vent on a roof vent. I think wall might be simpler, and it might make sense to drop the bathroom ceilings from 9 feet to 8 feet, and run the duct work through the false ceiling and out the wall. Requires 3 switches. Here is a 3-switch in a single unit.

Laundry-room fan: Panasonic FV-04VE1 WhisperComfortTM Spot Energy Recover Ventilator. Manual located at http://www.manualslib.com/manual/305650/Panasonic-Fv-04ve1.html. Requires 2 ducts. Ducts should be insulated to avoid condensation. Duct outlets must be at least 3 feet apart. Intake air duct must be at least 6 feet from dryer duct outlet. Requires just 0.15 amps at maximum power, so it could run on a shared circuit.

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Code note about exterior walls

As you probably recall, I’m trying to build this house as close to 1000 square feet as possible, because that is the largest allowed by county codes for 2nd dwellings on a single parcel. However is 1000 square feet defined? Well, it’s everything inside the exterior walls. So, if you have thick walls, you lose space to wall thickness. That’s a bummer for those who want to insulate well, since that means thick walls and thus less square footage. However, my architect brother-in-law said that he believed the code said the exterior walls end where the structure ends, so anything outside the exterior wall structure doesn’t count towards wall size. Specifically, if you have insulation, sheathing, siding, etc outside the structure, you ought to be good to go. Well, I did some code searching today and here’s what I found in Chapter 2 of the International Building Code:

EXTERIOR WALL. A wall, bearing or nonbearing, that is used as an enclosing wall for a building, other than a fire wall, and that has a slope of 60 degrees (1.05 rad) or greater with the horizontal plane. 

EXTERIOR WALL COVERING. A material or assembly of materials applied on the exterior side of exterior walls for the purpose of providing a weather-resisting barrier, insulation or for aesthetics, including but not limited to, veneers, siding, exterior insulation and finish systems, architectural trim and embellishments such as cornices, soffits, facias, gutters and leaders. 

EXTERIOR WALL ENVELOPE. A system or assembly of exterior wall components, including exterior wall finish materials, that provides protection of the building structural members, including framing and sheathing materials, and conditioned interior space, from the detrimental effects of the exterior environment.

So, “Exterior wall” isn’t entirely clear whether that includes insulation, but if you hop down to “Exterior Wall Covering”, you see that that includes anything on the exterior side of the exterior wall, including insulation, siding, trim, etc. Then they have a separate term, “exterior wall envelope”, to include exterior wall plus all the coverings. (And just as a reference for myself, Island County uses the 2012 International Building Code, which can be found referenced here: https://www.islandcounty.net/planning/building.htm, where it states “The 2012 International Building Code is in effect”.)

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Heating system notes

Part of building a well-insulated house is considering the kind of heating system you need. Ideally, all the money you spent on insulation should be balanced by being able to get away with a lower-capacity (and thus cheaper) heating system, and also offset by lower energy bills. So, the question is what to do. Some of the major choices for heating systems include:

  1. Propane furnace
  2. Electric furnace
  3. Radiant floor hydronic heating
  4. Electric resistance heaters
  5. Heat pumps
  6. Wood stoves
  7. And oh-so-many more

In version 1 of the house, the main heat source would have been hydronic radiant heat in the concrete slab. However, now the concrete slab is in the unheated basement, so that’s out. You can do hydronic radiant heating under wood floors, but you have to be super-careful with your temperatures because you run the risk of drying out the wood and warping everything.

A particularly efficient mechanism for heating is the heat pump. Fundamentally, heat pumps extract heat from the outside (although it is cold) and bring it inside. So, they don’t generate heat, but just move it. Because of that, they reach higher levels of efficiency than would even be theoretically possible with electric resistance heating systems. Back in Raleigh, NC we had a heat pump system in our house (as do most houses because a heat pump can also be an air conditioning system). However, when we had the heat pump replaced (just the heat pump and air handler) it cost $5000 and needed to be done by pros because it dealt with refrigerant lines (and that didn’t include the ductwork, which would have cost extra and takes up space!) But while searching the internet today, I came across a “mini-split” heat pump system, which is basically a ductless single-room heat pump. Since the house only has 3 rooms, one per room really isn’t out of the question. Also, it appears that you can owner-install it without too much trouble. Here is a link to the product.

So, for $725 each (so $2175 for the whole house), you get a heating and cooling system that you can control on a by-room basis. So, I think that may be the way to go.

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Styrofoam Lego Concrete House

So, a big question that has always been at the forefront of my mind is how to built the house. To minimize energy costs, I’ve always wanted a well-insultated house (note that the exterior walls were always drawn to be a foot thick – that’s actually the plan). However, there are various methods for doing this. One method is insulating concrete forms. These are basically blocks of Styrofoam that act as a form for a concrete wall, and will sandwich the wall after pouring. There are upsides and downsides to building with concrete. One thing that can be a blessing and a curse is that concrete has a huge amount of thermal mass. Thermal mass is ideal if the the average of daytime and nighttime temperatures is a comfortable living temperature. Then thermal mass will keep you cool during the day and warm at night, because it will even out the extremes. However, concrete is a horrible insulator. Concrete has an R-value of 0.08 per inch. Soft wood will give you 1.25 (more than 15 times as much). Even single-pane glass will give you more insulation than a half foot of concrete. However, if you have concrete sandwiched in a large amount of insulation, its tendency to leak heat will be blocked by the enormous amount of Styrofoam on the other side. There will still be a large amount of thermal mass in the middle of the wall, but there will be multiple inches of insulation of either side of that mass. So, I think that will help control the difficulty one would have in heating a concrete structure, as well as maintaining proper moisture levels inside the house. (If you have poorly insulated concrete in a cool climate, the walls will be incessantly cold, and will cause condensation and thus mold.)

The big advantage of building with concrete to me is that it will easily enable a daylight walkout basement. (See notes at the bottom of About the House. Basically, a basement is not part of the square footage, so it won’t make us break the 1000-square-foot rule for second houses.) Basically, you have to do concrete walls for a basement, but as I noted above, normal concrete is just too non-insulated and it will draw in coldness from the outside ground. (And all the heating and moisture problems that go with that.) However, if I’m using insulating concrete forms for the main walls, it’s not too much of a stretch to go a bit further and use insulating concrete forms to build a basement as well. A bit advantage of having a basement is that you have super-easy access to all the utilities. Plumbing just drops through the floor, and then you have a nice, dry, open, tall area to work on your plumbing. I really dislike crawl spaces. They are dark, damp, and not tall enough to work in. I like slabs, but they lack flexibility for changes. A basement allows you extra-easy access for all your plumbing and electrical work.

Also, the insulating concrete forms allow for more flexible house shapes than some of the kits I looked at previously. So, now I’m considering a 50-foot by 20-foot house in the basic configuration of a left-bedroom, a right-bedroom and a center kitchen-living-dining area. A spiral staircase would lead to the basement. All utilities (water heater, breaker box, etc) would be in the basement.

So, now that I’ve gone on and on about the advantages, here are some pictures of some insulating concrete forms that I picked up from Quad-Lock.DSC_6570

They are basically Lego blocks. You have two parallel rows of Lego blocks, held together by plastic ties. The plastic ties keep the forms from sliding away from each other. They also serve as a point to hold both horizontal and vertical re-bar. And then they also serve as a material for affixing siding on the outside and drywall on the inside. (However, it seems that you can also apply stucco directly to the outside, which will probably be my path. Nadja is from Germany, and stucco is a very common German look and I think she’d appreciate that.)DSC_6571

Quad-Lock open DSC_6574DSC_6575

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