Best ways to lower housing operating costs in Mass? (rental, credit)

[Shrewsburried]

Originally Posted by Louisville Slugger

Does yours have a "Dry Mode"?

According to the manual this mode is used to:

"Dehumidify your room. The room may be cooled slightly. Temperature cannot be set during DRY mode."

I tested this mode out and it did a great job of removing the humidity from the house. The temperature pretty much reached what I would set it at if I had put it in COOL mode.

I am trying to figure out which mode is more efficient and when I should use either.

It does, but I only use the mode post AM showers when humidity ramps (my fancy Panasonic fan is still boxed in the utility closet ... some day). I tried utilizing the Dry mode for longer stints, but it always overshoots temp settings by a large margin (64 deg versus 73). I suspect this is due to an oversize indoor unit despite it only being a 6k FH series high wall. It was the smallest ductless offered, but apparently not small enough.

Ideally, I would have installed a single zone 9 or 12k unit to a ducted indoor unit for better turndown/humidity control, but running ducting to both bedrooms would have meant opening up A LOT of blueboard plaster walls and some additional soffit build outs ... I lacked the motivation and time to do so.

I did split my 4 zones into 2 separate outdoor units - on 20k and one 24k. The latter was sized off a somewhat aggressive manual J I did myself. I wanted efficient modulation under normal winter temps and not our random 5 degree evenings ... for those nights I have a boiler or a wood burning insert. Options I have many. The 20K is oversized some, but again, I went as small as I could but it is still not small enough.

I split the load into two outdoors as the cost differential was minimal, line set routing easier, and SEER numbers higher ... in theory. It also gives me a minimum turndown of 6k btu during shoulder seasons versus 12k btu. Ideally I would have zoned 1:1 (indoorutdoor) as the min turndown specs (modulation) are much better for single zones, but my outdoor locations are limited and I wanted every unit ground accessible.

[wolfgang239]

2 units is one way to do it, but their minimum turn down if you happen to be running one unit on each isn't to far off from what you'd get on my 48k. They are great though due to how many scenarios you can adapt them to, for example you may have set it up to really only run one system at a time. I like having one Indoor unit in each area to dial it in perfectly room by room but you definitely take an efficiency hit on the multis. Even a 6k is way oversized for most bedrooms.

[Shrewsburried]

Originally Posted by wolfgang239

2 units is one way to do it, but their minimum turn down if you happen to be running one unit on each isn't to far off from what you'd get on my 48k. They are great though due to how many scenarios you can adapt them to, for example you may have set it up to really only run one system at a time. I like having one Indoor unit in each area to dial it in perfectly room by room but you definitely take an efficiency hit on the multis. Even a 6k is way oversized for most bedrooms.

My impression was that the 42K+ BTU systems have a 12k min turndown versus 6k for the smaller multis. I suppose depending on your number of zones and loads the 12k min might be a reasonably low.

I run the 24k unit only in the shoulder seasons, which covers the main living area (highest load) and home office/guest room. The second outdoor unit remains off unless overnight lows dip below norms.

If I were to do it over again, I would have zoned our Master/bath and son's bedroom as separate 1:1 systems. The min turndown of the 1:1s is right around 1.6K per (or 3.2K combined versus 6k). I didn't do this as the multi provided a rather clean install (https://imgur.com/a/mhKAsPY), but at the cost of optimized performance ... kind of a s___ compromise past-tense me did not fully appreciate.

[GeoffD]

Originally Posted by Shrewsburried

1) Super insulate house. If residing and/or reroofing, add exterior foam to create a thermal break. If replacing windows, use high quality casements (e.g., Marvin Integrity). Air seal where possible.

2) Once heat loss is controlled, pair solar systems with heat pumps.

I’ve written about this before but I screwed up 10 years ago and installed an A/C-only mini-split instead of a heat pump. I’m not in the house in the winter so I don’t have a big gas bill heating to 50F but it would have been nice to have the redundancy and the option to mostly heat with solar electric.

Personally, I think the big win for solar is plug-in hybrid or electric cars.

[Louisville Slugger]

Originally Posted by Shrewsburried

It does, but I only use the mode post AM showers when humidity ramps (my fancy Panasonic fan is still boxed in the utility closet ... some day). I tried utilizing the Dry mode for longer stints, but it always overshoots temp settings by a large margin (64 deg versus 73). I suspect this is due to an oversize indoor unit despite it only being a 6k FH series high wall. It was the smallest ductless offered, but apparently not small enough.

Ideally, I would have installed a single zone 9 or 12k unit to a ducted indoor unit for better turndown/humidity control, but running ducting to both bedrooms would have meant opening up A LOT of blueboard plaster walls and some additional soffit build outs ... I lacked the motivation and time to do so.

I did split my 4 zones into 2 separate outdoor units - on 20k and one 24k. The latter was sized off a somewhat aggressive manual J I did myself. I wanted efficient modulation under normal winter temps and not our random 5 degree evenings ... for those nights I have a boiler or a wood burning insert. Options I have many. The 20K is oversized some, but again, I went as small as I could but it is still not small enough.

I split the load into two outdoors as the cost differential was minimal, line set routing easier, and SEER numbers higher ... in theory. It also gives me a minimum turndown of 6k btu during shoulder seasons versus 12k btu. Ideally I would have zoned 1:1 (indoorutdoor) as the min turndown specs (modulation) are much better for single zones, but my outdoor locations are limited and I wanted every unit ground accessible.

I tried using Dry Mode 24/7 for three days straight and it does a good job of keeping the humidity around 50%, temperature during the day around 68 to 70. The only weird thing was when I woke up in the morning and went upstairs the temperature was 66. Usually I keep it around 70. That has been the only difference so far.

Since my bedrooms are in my finished basement and my 12K unit is upstairs all the cold air drops to the basement and it remains 50% humidity down there and 70 degrees most of the time. I do have another minisplit in one of the rooms in the basement, but it rarely ever kicks on in the summer. The only time it does is when I have the door closed and spend a few hours in there watching movies or something. My home theater equipment increases the temperature in the room enough to get the minisplit to kick on.

I guess I'll have to play around with the modes and settings and find out what works best for me and my space.

[Shrewsburried]

Originally Posted by Louisville Slugger

I tried using Dry Mode 24/7 for three days straight and it does a good job of keeping the humidity around 50%, temperature during the day around 68 to 70. The only weird thing was when I woke up in the morning and went upstairs the temperature was 66. Usually I keep it around 70. That has been the only difference so far.

This has been my experience. The "room my get colder" warning is rather understated if dealing with smaller spaces.

I've since decided to installed a dehumidifier (as of yesterday) ... detaching humidity control from temp control seems like the more intelligent approach. It also means that on those dank summer nights, the dehumidifier might be the only system running.

[mdovell]

Originally Posted by GeoffD

Personally, I think the big win for solar is plug-in hybrid or electric cars.

I was kinda thinking of that. Technically I think 220V can charge most although the connections are usually a washer or drier at least for fast. Plug in hybrid would be good although I don't know how many used ones are out there. Tax incentives vary by state and I think the fed is pulling the plug.

[wolfgang239]

Originally Posted by mdovell

I was kinda thinking of that. Technically I think 220V can charge most although the connections are usually a washer or drier at least for fast. Plug in hybrid would be good although I don't know how many used ones are out there. Tax incentives vary by state and I think the fed is pulling the plug.

You can get an off lease Chevy Volt for like $15-20k depending on options. I had solar, heat pumps and a plug in hybrid on my last place. Once you go all in you really get to reap the benefits.

Most people only need something like 50mi of range to do their daily commute and most of their driving, which can easily be accomplished overnight on a regular 20A 120v circuit. A volt gives you that plus as far as you want to go on gas. The nice thing about a plug in car is that you are always on a "full tank" when you wake up in the morning.

[simplexsimon]

Not an "operating" cost, but a loan refinance may knock a decent chunk of interest off your monthly payment right now.

[GeoffD]

Originally Posted by wolfgang239

The nice thing about a plug in car is that you are always on a "full tank" when you wake up in the morning.

If you're using your solar panel to charge it, I sure hope you have a night job.