Community: Mechanicals

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6 Answers

Installing Fujitusu 15RLS3H split system - What wired remote is best for achieving accurate set points?

Fujitsu offers two wired thermostats for the 15RLS3H package. It seems like others are having problems with getting accurate temperature control using only the thermostat in the indoor unit, so I was looking to get the proper wired thermostat right away.

The two options are UTY-RVNUM and UTY-RNNUM.

The UTY-RVNUM thermostat is backlit and has a nicer looking interface, but it's over $300 for just the remote.

Asked By Rick Van Handel | Mar 7 16
16 Answers

Make up air strategy

This is for a home being constructed in zone 7/8 Colorado mountains. The home will be built with attention to air tightness and will be blower door tested, an ERV will be installed. Heating system will be a direct vented propane boiler with in floor radiant and an indirect water heater.

The house will have a 600 CFM range hood and two electric clothes dryers, these appliances will need make up air provided in order to operate correctly without depressurizing the house.

Asked By Chris Armstrong | Feb 26 16
1 Answer

Good bath fan for continuous use (6" joists)

One of the first things I did when I bought my house about 11 years ago was replace the bath fan with a Panasonic WhisperFit. Recently, I had a blower door test done and it's clear several years of tightening up the house means I'm (way) overdue for some mechanical ventilation. I've decided to go exhaust-only with about 30CFM average. What I'd like to do is install a WhisperGreen, but it doesn't appear any of those fit with my 6" ceiling joists? My best option seems to be the latest version of the whisperfit (or keep my current older model).

Asked By Erik Addy | Mar 8 16
9 Answers

Mini-splits cause settling & cracking of drywall?

I am pretty committed to the idea of Mini Splits for various reasons I've read about on this site, but our contractor is putting up resistance, saying that we need to have heads in the bathrooms, otherwise temperature differentials will lead to settling and cracking of the drywall, which I have been completely unable to substantiate in online research. Is there any truth to this?

Asked By Joseph Yount | Mar 7 16
1 Answer

Does ASHRAE’s Residential Ventilation Standard 62.2 make sense in a cold climate in a pretty good house?

I'm designing a pretty good home (R33 walls, R60 ceiling, R7 windows and less than 0.6 air changes per hour at 50 Pascals pressure) in Zone 6 and I'm trying to configure a balanced ventilation system. I read several Green Building Advisor articles on mechanical ventilation, including "How Much Fresh Air Does Your Home Need?" which pointed out the potential for moisture issues in warmer climates when designing to ASHRAE’s Residential Ventilation Standard (Standard 62.2), which sets the minimum ventilation rate at 7.5 cfm per occupant plus 3 cfm for every 100 square feet of occupied floor area.

Asked By Brad Lystad | Mar 7 16
15 Answers

Radiant Flooring / GeoThermal / Solar

Statements
- We are building a house and are putting radiant flooring on both floors between the joists.
- We will install solar panels after we are finished building.
- Our house will be a tight house with the Atlas LCi-SS system installed in place of the OSB, PolyISO and wrap.

Asked By Michael England | Feb 27 16
5 Answers

Best natural gas water heater for inside a home’s envelope?

Climate - 5a
Air-sealed R32 walls.

My clients are looking for the best 50 gal. natural gas water heater for the home we're building them.

Asked By Nethaniel Ealy | Feb 25 16
3 Answers

Keep the old duct layout or switch to two branches?

Trunk A has rotted out and is filled with nasty old fiberglass lining, so I need to replace it. While I am at it, I wonder if I would get better performance from registers, if I also replaced the 8X8 existing branch with two 8" branches straight off the trunk.

Asked By Apollo S | Feb 26 16
20 Answers

Can you get radiant cooling using forced air systems?

I am planning on installing my VRF ac unit air vent above a metal false ceiling so that the ad cools the metal ceiling and the cold ceiling cools the room by radiant cooling . Is this practical ? Has any one any experience about something like this ? Or if you have heard of someone who might be using a similar system ?

Asked By Ankush Mahajan | Oct 28 15
9 Answers

Need ducting reconfiguration advice. Moving ducts by 1 joist bay

I have several issues that I want to mitigate by cleaning up forced air system that takes care of my living room and kitchen.

There are two problems:
#1. 20X10 and 12X8 supply trunk ducts have nasty fiberglass lining I need to remove (if not just replace the ducts). See picture for the horror show
#2 I need to move Branch A and Branch B by one joist bay, because right now those fill the band joist and nicely warming up my uninsulated joist. Need to insulate that. I don't think 12X8 branches will survive removal, so 'tis the time to resize, if necessary with preferably round trunks

Asked By Apollo S | Feb 18 16
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