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1 Answer

Manual J load done — trying to determine kWh for ductless heat pump

Here are my numbers for 700 square foot guest home, zone 4b
Heat Load 9,725 btus/hour
Cooling Load 7,503 btus/hour

I know there are several variables but the unit I am looking at is a Ceiling cassette rated at 20.2 seer 12k btu unit

My question is there anything that has been published that could give me a good estimate of what my kWh could be.

Or some numbers at different temperature conditions

Thanks
Richard

Asked By Richard Riso | Jul 20 17
24 Answers

Unvented Cathedral Ceiling Interim Remodel

I have a roof problem on a small section of 4/12 above the bathrooms. It is only about 15 feet by 10 feet of insulated ceiling. Background information.... We are in Enumclaw, WA, which is zone 4C, I believe.

My home was built in the early 80's as a Justus Homes kit. All of the ceilings are unvented cathedral construction as follows:
2x6 tongue and groove on the interiors
15 pound felt
2x6 on edge at 24 inch spacing

Asked By user-6883899 | Jul 11 17
1 Answer

Yep! Cathedral ceiling: To vent or not?

Okay, so I have tried to do all my homework before asking the question but I seem to be confusing myself more with every article and question I read including Martin's "All About Attic Venting" article. Simple 4/12 cathedral roof with no intrusions (hips or the like) on a new construction home. Climate Zone 6 with high snow load potential but infrequent. Originally I was going to do a metal roof but value engineering is pushing me to shingles and my dilemma. The rafters are 2x14 TJIs so I have some room but I am aiming for upwards of R-60. Here are the two scenarios I am contemplating.

Asked By Bevan Arch | Jul 20 17
1 Answer

Humidity and negative pressure

A customers home (zone 4 non-marine) has condensation problems (summertime) on a particular HVAC duct. Upon inspection the %RH was at 60%. There is a whole house dehumidifier hooked in with the HVAC System (Fan runs at low speed continuously) Bathroom exhaust fans are backflowing and letting in a significant amount of heat, and when opening the front door one can feel the hot air entering the house. There is no ductwork in the attic, it is all in the basement.

Asked By Jeff Classen | Jul 20 17
4 Answers

Insulating balloon walls

High I am renovating a 1927 Dutch colonial with balloon wall construction. Th attic is finished but will be taken down to exposed walls and rafters. The exterior will be resided on the second level with Hardy board fibercement clapboards. The ground level is one layer of brick over wood sheathing. The roof will be replaced with an imitation slate product (DaVinci roof scrapes). All the windows were already replaced (Trim line) Aluminum clad wood thermopane windows. My question is about insulation. I will be cutting a ridge vent.

Asked By eh413 | Jul 20 17
8 Answers

Housewrap

Greetings all. We built our house 5 years ago with much good guidance from this site. We installed a wall assembly with 1/2 inch osb, then a layer of housewrap, then a layer of 1/2 inch foam board with the seams sealed and flashed to outtie type windows. We installed Certainteed cement board siding. This siding had manufacturing issues and was subject to a class action settlement because it would crack, etc. We have several cracks, etc. We have filed for the claim and are preparing to replace our siding with James Hardy. Wish we had gone with that brand in the first place.

Asked By Aron Robinson | Jul 14 17
1 Answer

Build my own SIPs, or just frame it?

I am in the planning phase of building a second home and a shop on my property. I have access to as much insulation material as I need in 22" wide and various length (from 36" to 64") rigid foam insulation (door cut outs with the skins still on r 6.25 and 1 3/4" thick) for free!

Asked By Mathew Bean | Jul 20 17
1 Answer

Insulation question and new construction.... thoughts ?

New construction, we are doing a non-vented attic to keep our HVAC ductwork in a conditioned space with foam on the roof deck. Come to find out, we can put foam in all the walls vs using bibs for the same price which surprised me. This will make for a tight house and this brings the question in my mind "what type of mechanical ventilation"? House needs to breath and have a good exchange of air.

House is a 2 story and about 2700 sq ft. 2 HVAC units will be installed. Biggest concern is a good ventilation system..

Asked By Thomas Roberts | Jul 20 17
3 Answers

Can I use two layers of Tyvek in a wall assembly without moisture problems?

I am building a house which has a REMOTE wall system in it (foam "outsulation"). Although I passed on the relevant information to the builder, who is usually on top of the details, he managed to mess up with the window bucks.

The wall structure is 2x4 studs (with R13 cavity insulation), plywood sheathing, Tyvek Drain Wrap (wrinkled stuff) 2 layers of EPS foam of R10 each sealed with Siga Wigluv tape, then 3/4" plywood furring strips followed by wood siding.

Asked By Gary Dick | Jan 11 15
5 Answers

Will R-70 cellulose sag ceiling drywall 24" o.c.?

My plans call for an R-70 ceiling of loose-pack cellulose in double-netted bays between trusses 24" o.c., with 5/8" Type X drywall holding it up as my air barrier. My installer says this will weigh about 2.55 lbs/sq/ft. Is this too much? Will it sag over time or pop screws? Do I need to use some special (expensive) low-sag drywall? I don't want to go to the expense and lost clearance of, e.g., an OSB layer above the drywall.

Anyone have experience with this?

Thanks.

Randy

Asked By Randy Jorgen | Jul 16 17
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