Ductless Mini Split vs Conventional Furnace / AC

[overcoil]

Originally Posted by DETRoadster

That sounds miserable!


Great feedback, everyone! We have a design review with the architect in a week. I'll dig into his recommendation for a mini-split further when we meet.

To put into perspective.

In my brothers old home the central air with dehumidifier need special cleaning to prevent growth.
Many refrigerator ice-makers and water dispensers have growth.

Well water compared to municipality water. I know my friends well water is high maintenance I think due to calcium deposits.

It seems anytime you use water for HVAC or refrigeration then there will be certain regimens for maintenance.

[Frostynorth]

Originally Posted by vreihen16

Back in the early 1990's, my employer had a high-pressure small-duct AC system installed in two office suites across the hall from my office at the time. It was supposedly the bleeding edge of AC technology at the time, using several ducts the size of vacuum cleaner hoses into each room. When it was new, the airflow was so strong that it used to blow papers off of people's desks!

Those high velocity systems were garbage and didn't last on the market very long. I've only ever seen it once, and that was years and years ago.

Originally Posted by Caravaggio

Had Mitsubishi ductless in my last house. The house was a very open design and the cooling was excellent. Also the exterior unit was small and architecturally it was almost unnoticeable and didn't mar the minimalist exterior design. This was an earlier system and didn't have heat.

The one thing about the maintenance was, that I needed the HVAC people to come out yearly and disinfect the inside of the indoor unit. They sprayed a disinfectant over the coils and had a drip bag underneath, a very extensive cleaning regimen. If this cleaning wasn't done a fungus formed on the moving vanes etcetera and the unit would spew out water droplets.

Mitsubishi makes some of the best ductless systems.
Cleaning them isn't incredibly difficult, they are pretty easy to take apart when needed. Like a regular furnace, keeping the filters clean helps prevent dirt from getting on the coils and eventually clogging the condensate drain.
The fungus build up would vary depending on use and climate.

[3.0L]

I had two ductless AC systems installed 5 years ago and we are very happy with the results. They cool the house well (2-story) and are very quiet. Zero problems.

The primary reason we went with ductless is because our existing ducting was inadequate (4" uninsulated) and would've had to be replaced if we went with a conventional AC system. All of our heating ducting is located in the ceiling of the first floor and it would've been a move-out-until-completed mess, not to mention very expensive.

If I were building a new home I would definitely have conventional HVAC system installed with appropriate ducting.

[DETRoadster]

Originally Posted by TheWatchGuy

Unless your house is small, mini-splits arent a great choice imo. They are great for cooling a room, but unless you only have a few rooms, or never go in some rooms, youre going to have some pretty big temp differences unless you install them in every room.

if i was going new build, forced air and ductwork would be my go to for anything with more than a few rooms. If i was retrofitting an existing house, minisplit would be the easiest and most cost effective way to do it. Or if i built a smaller house with only a couple bedrooms and an open space kitchen/dining/living room, might go for the minisplits. in my current house though with 3 floors (main, upstairs, basement), 3 "common areas" (Living room/kitchen, loft space, basement game room/bar room/tv area) and 6 bedrooms, putting in a bunch of minisplits wouldnt be a great choice over the traditional setup. We'd have 10+ units around the house.

It will be a small house. 1800 to 2000 sqft. Open concept LV/DR/Kitchen with 12 to 14 foot ceilings and lots of windows. So, significantly more heating and cooling needed in there vs. the bedrooms. A tough job for a conventional system. I think here, a mini-split system with individual controls for the bedrooms vs. the "great" room might shine. I just need to get over my fear of reliability and maintenance.

[overcoil]

Originally Posted by DETRoadster

It will be a small house. 1800 to 2000 sqft. Open concept LV/DR/Kitchen with 12 to 14 foot ceilings and lots of windows. So, significantly more heating and cooling needed in there vs. the bedrooms. A tough job for a conventional system. I think here, a mini-split system with individual controls for the bedrooms vs. the "great" room might shine. I just need to get over my fear of reliability and maintenance.

just so you know in case your installing ceiling fans, of course double check.

But the Mitsubishi instructions said not to run a ceiling fan in close proximity or in the same space as the indoor ductless wall unit. Obviously I'm assuming a fan will ill effect the temperature sensor.

I'm in a condo now with a heat-pump HVAC and I liked life better with the ductless unit.

[3.0L]

Originally Posted by DETRoadster

It will be a small house. 1800 to 2000 sqft. Open concept LV/DR/Kitchen with 12 to 14 foot ceilings and lots of windows. So, significantly more heating and cooling needed in there vs. the bedrooms. A tough job for a conventional system. I think here, a mini-split system with individual controls for the bedrooms vs. the "great" room might shine. I just need to get over my fear of reliability and maintenance.

Our 2-story home is 2000 square feet with the kitchen, master bedroom, dining and living rooms on the second floor. So, we had a 9000 btu ductless unit installed in the master bedroom and a 12,000 btu unit installed in the living room. Also worth mentioning is that we have vaulted ceilings on the second floor, so do not benefit from an attic.

During heat waves of 105+ days we run both units on fan settings of 1 to 3 (out of 5 steps) and the house temps hover around 80. And since cool air tends to descend, the downstairs stays about the same temp. During less fierce hot spells, it is easy to keep the house temps around 75 with low fan settings. We have never had to run the units on fan 4 or 5.

And oh yeah, both units are reversible for heat if needed. We have natural gas for heating, but it's nice to know we have back up.

Another thing to consider is that we had to hire an electrician to run the required 220 AC power to each of the outdoor portions of the units.

[Kolyan2k]

I heard Mitsubishi and Bosch central systems are the best. They were all special order so I had to settle with cheap stuff, but I don't have much regrets. It works and it's super quite.

One thing many people don't consider and I think it's way more important then brand names, it's dehumidifier if you need one and ERV is a must have for any house. Best decision I made was ERV. Last year with all inflated prices it cost me $18k to install 2 new systems for $2500 sqft (attic and basement). As I remember Bosch units were around 25k, but did have a pretty big rebate

[Kolyan2k]

Ps I also have solar panels from previous owner. I haven't paid a single electric bill in over a year. I forgot what SER units are, I think it's minimal what's considered energy efficient just enough

[DETRoadster]

Originally Posted by Kolyan2k

I heard Mitsubishi and Bosch central systems are the best. They were all special order so I had to settle with cheap stuff, but I don't have much regrets. It works and it's super quite.

One thing many people don't consider and I think it's way more important then brand names, it's dehumidifier if you need one and ERV is a must have for any house. Best decision I made was ERV. Last year with all inflated prices it cost me $18k to install 2 new systems for $2500 sqft (attic and basement)

What's ERV?

[Kolyan2k]

Originally Posted by DETRoadster

What's ERV?

Energy recovery ventilator. Brings fresh air from outside, takes out stale air from bathrooms , passively heats and cools intake air and filters it. No need to open windows

[DETRoadster]

Originally Posted by Kolyan2k

Energy recovery ventilator. Brings fresh air from outside, takes out stale air from bathrooms , passively heats and cools intake air and filters it. No need to open windows

Thanks! I'll look into that. Sounds like a cool benefit in the mini-split category.

[Kolyan2k]

Originally Posted by DETRoadster

Thanks! I'll look into that. Sounds like a cool benefit in the mini-split category.

You can add it to mini-split system, but you need all the duct work. If you have central air then it can use existing ducts. Hvac guys who did my ACs installed ERV for free, I just paid for the unit

Zehnder makes the best ones, but expensive, they come with all ducts etc. Read it's a nice DIY if all walls/ceilings are open

[Torgus]

Originally Posted by DETRoadster

20k in solar panels just aint making the cut.

At least solar has a payback period and then you start to actually make money off of your investment after 7 years or so depending on what state you are in. Unless you do one of those no money down leases which I DO NOT recommend.

[DETRoadster]

Originally Posted by Kolyan2k

You can add it to mini-split system, but you need all the duct work. If you have central air then it can use existing ducts. Hvac guys who did my ACs installed ERV for free, I just paid for the unit

Zehnder makes the best ones, but expensive, they come with all ducts etc. Read it's a nice DIY if all walls/ceilings are open

Thanks. I'll look into it. It's new construction so its a clean sheet of paper. Anything is possible.

[DETRoadster]

Speaking of mini split systems, my neighbor (house on the left) is having one retrofitted into his house right now. The jackass installer seems to think my roof is an acceptable place to stretch the refrigerant line out onto. What a jackass. Who does that?! :