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10 Answers

Water-source heat pump sizing

My 2-ton Carrier water source heat pump needs replacing. It's a condo, so I own the heat pump & handler, but not the water loop. I think I'm going to replace with another Carrier, but I'm considering downsizing to a 1.5-ton unit.

Asked By David Hicks | Mar 19 15
3 Answers

iQ drive vs mini-split?

My last house (2700sf)was made with SIPS and had a traditional 16 SEER heat pump. It worked fine and despite a convoluted layout only had minor airflow issues. Now I'm building a smaller house (2000 sf) with double stud walls and better windows so I expect the envelope to perform better than my last house with 4" SIPS (climate zone 4 - east TN...go vols and all that stuff). I have been thinking of going with minisplits because they are all the rage...but with the inverter's used in Nordyns iQ drive couldn't it be close to as efficient?

Asked By Andrew Bennett | Apr 20 15
21 Answers

Is it reasonable to use 3/8" PEX supply lines to all fixtures?

I am planning the plumbing system for my Net-Zero Energy home that is being built to Passive House standards. I will be using PEX tubing with a manifold system using home runs. I designed the house so that the bathrooms and laundry room are centrally located, making the supply runs pretty short. I want to minimize the amount of water and energy being used and low-flow fixtures provide plenty of water for my needs (2.2 gpm at sinks and 2.5 gpm for showers).

Asked By Gerald Blycker | Mar 11 14
5 Answers

Laying out mini-splits for a new home

I have a new home in the design stage and have been working with with my HVAC sub and the wholesaler to layout and locate mini-splits for the project. The house will be 2550 sq.ft. on a slab with R40 walls, R75 ceiling and very tight. We are in zone 5, floor plan is attached. We will be installing an ERV for fresh air.

The HVAC guy and the wholesaler want to put a head in each bedroom as well as the entry, office, family room and great room and run them off of 2 separate outdoor units. Their concern is to provide uniform temps throughout the house.

Asked By Terry | Apr 17 15
5 Answers

Multisplit temperature control per zone

I am considering a multisplit heatpump system for our 3000 s.f. two-story renovation located in Chicago, Zone 5. I like the idea of a multisplit system for its high efficiency and zone control. I would like to provide 1 unit per bedroom using ducted interior units that supply conditioned air to each bedroom.

Asked By AlokKhuntia | Apr 14 15
23 Answers

Mitsubishi mini split behaving very differently with external thermostat vs. without

I am able to monitor my home's electricity use and I always thought it was a little weird that my Mitsubishi FE18NA heat pump seemed to constantly be spiking up and down, considering that the whole idea of the inverter-driven compressor is that it can run smooth and steady... fast forward to yesterday when I received my MHK1 thermostat and hooked it up. Suddenly, the power usage was steady as a rock.

Asked By Nick Welch | Jan 6 15
6 Answers

Yet another minisplit sizing question

I'm building a new home in Washington state (Seattle area, Marine 4C) and it should be fairly well built as I'm keeping the design simple, with rectangular dims and minimizing penetrations in roof/wall/floor. The builder claims "energy efficient" methods but they all do. Washington does require fairly progressive standards and a blower door test is standard fare. I won't have results until the building is done and I'm planning for my mini-split now.

Asked By Kevin Haskins | Apr 6 15
1 Answer

More wet fiberglass

Some of y'all might remember this picture...
http://techno-fandom.org/~hobbit/hse/myduct.jpg
and the discussion that went around it, concerning careful backoff
[from the wall] and sealing-up of the outer duct sheath to make sure
no water infiltrated into the fiberglass between. This was for the
intake duct on my HRV setup, the coldest part, and after retrofitting
same on my HRV setup accordingly it was fine all this winter.

So I was downstairs putting the snow shovels away [wishful thinking?]
and happened to bump the end of the *exhaust* side duct, which

Asked By Hobbit _ | Mar 31 15
19 Answers

Fresh air distribution for hydronically heated house?

Currently have a leaky hydronically-heated house.

I plan on removing the siding, installing blueskin VP peel-and-stick, then 2 layers of Roxul R6 ComfortBoard IS from the roof right down to the footings.

Because this should really improve the air leakage, how should I get fresh air in/out of the house to control humidity / air quality / etc?

Do people run a set of air ducts throughout the house from a HRV?

One of the appeals of using hydronic heating is that sound / dust transmission is significantly reduced.

What would you recommend??

Thanks!
.../j

Asked By John Charlesworth | Mar 26 15
3 Answers

Manual J - Calcs - Mini Splits

Zone 4B - 3,300 sqft - 2 story - R10/R25/R60 with R8 windows - open floor plan design

The calcs came in at 3.25 tons heating/cooling. Two ductless minis per floor:
3 - 9,000 Btu Mitsubishi Hyper Heat Pumps - 26 SEER - 10.5 HSPF
1 - 12,000 Btu Mitsubishi Hyper Heat Pump - 26 SEER 10.5 HSPF

$12,000 installed (P&L) for all units - 10 year warranty

Asked By Peter L | Mar 26 15
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