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5 Answers

Lunos e2 ductless HRV system vs. ducted system

I am building a net zero house, 2000 SF, 2 stories. Can you tell me the pros and cons of the Lunos e2 ductless HRV system vs. a ducted system? The rep told me that 3 pairs of the Lunos e2 would be about right.

Asked By Courtney McCracken | Dec 8 16
0 Answers

What capacity rating should be used for sizing ductless heat pump?

The easily obtainable heating capacity information for ductless heat pumps are generally listed as Btu/h at 47 degrees and Btu/h at 17 degrees. These don't appear to line up with the expanded capacity charts which can (sometimes) be found with some digging on manufacturers websites. Let's look at the Fujitsue ASU9RLS3:

It's capacity is readily reported as:
7,0000 Btu/h @ 17 degrees
12,000 Btu/h @ 47 degrees

However, if I look up the expanded heating capacity chart, it reports the Total Capacity as (assuming 70 degrees indoor temperature):

Asked By James Reider | Dec 9 16
4 Answers

Airflow around mini split compressor

Hi, the installer for my Fujitsu 15RLS3 installed the lineset in such a way that I think it restricts airflow behind the compressor quite a bit. See the attached photo. They wrapped the lines in a circle a bunch of times between the back of the unit and the wall to deal with the fact that the outdoor compressor is less than 15 feet from the indoor unit. In any case, do you think this restricted airflow affects efficiency or longevity of the system and I should ask them to put the lines elsewhere ? Is this way of installing the system even in line with manufacturers instructions?

Asked By matthias paustian | Dec 8 16
12 Answers

Minisplit questions

-I'm in zone 4, midwest US, and am about to buy a ductless split system for my main structure and the addition I'm finishing now. I am concerned as three of the five rooms I am putting them in are pretty oversized (~2600k btu load cooling, using the 6k heads) and the rep is saying I should go with the H2i. He said if I never need the low temp operations, the heater was worth the money.

Asked By Mike M | Dec 5 16
7 Answers

Is this a valid way to measure heat load?

Our manual J calculation said that the heat load of the house is about 30K at about 65 degree delta T. (It was more precise than that but I don't have the report handy, so I am going from memory.) I am hoping to confirm that the actual load is not too far away from that before we get into really cold weather.

Asked By Reid Baldwin | Dec 5 16
6 Answers

Mini-split energy usage

My first winter with a Mitsubishi ductless 15000 BTU (MSZ-GE15NA & MUZ-GE15NA). It's been in the low 30s in Seattle the past few days. I attached the electric usage recorded by my e-gauge. In the past (warmer temps) the usage curve is pretty flat. Now it's pretty jagged. Is it working properly (i.e.efficiently)? Thanks.

Asked By S K | Dec 5 16
2 Answers

HVAC Multifloor return system - Should I get grills with dampers to control velocity?

I am designing the new HVAC system for my home. I plan to do a 4 zone system, lennox SLP98UH090XV60C

Attached is a diagram for a visual.

I am getting into the return ductwork. To my understanding it's good practice is to have a return grill on each floor and it will better circulate air. Also, I separated them into two zones to help with noise transfer between floors.

Asked By Jamie B | Dec 2 16
7 Answers

Domestic hot water heat recovery: Two systems or one?

We have a large footprint house with multiple bathrooms. The Power-Pipe product seems to be an excellent way of recovering shower waste heat. The question is how to deal with multiple bathrooms that are more than 20 feet apart in a 3 story house. A central drain would be an easy otion and allow the use of one power pipe BUT the hot water woudl need to traverse a great deal of PVC pipe before getting to the power-pipe. It would also be complicated to plu,b to feed from the power pipe to to the mulitple showers drawing from it (in order to plumb the cold side of each).

Asked By Edward Cambridge | Nov 25 16
13 Answers

Looking for advice on a new build heating plan

I am trying to figure out the best solution for heating our new home and I would greatly appreciate any suggestion from the wise folks here.

Asked By Tim Burke | Nov 24 16
40 Answers

Domestic hot water and space heating

I am trying to put together a system that can deliver domestic hot water and heat the house. The colonial house is in Brooklyn, NY ( zone 7), 29' x 33' and consists of 2 floors + basement. I am doing complete renovation and already removed all walls throughout the house and will use closed cell foam insulation in all walls and roof. I plan to run Pex in joists for both floors and I am thinking of using baseboard in the basement.

My questions are:

Asked By Vladimir Polyakov | Nov 3 16
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