Installing a Ductless HVAC System
Updated: Aug 31
(My First RTTPYO Project)
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About the RTTPYO Series
RTTPYO stands for Removing Things That Piss You Off — the small home problems we tolerate for years before finally fixing them.
In this series, I tackle one everyday annoyance and show how a simple design change can make a space work better.
In this post: a piecemeal HVAC system gets an overhaul.
When I bought my condo, Portland weather had started to change. Winters got colder. It snowed more often, and the snow stayed longer. My condo’s ineffectual wall heating units were hideously expensive to run. I bought a Vornado space heater and carried it from room to room all winter to keep Zoey and me from freezing to death.
When the Vornado wasn’t running, Zoey would rely on the bedroom wall heater to stay warm.
Summer started arriving earlier, staying longer, and was definitely hotter. Since I worked in an air conditioned office, most nights at home I was able to make do with a fan.
Then I started working from home. My office faced west on two sides and by noon was scorching hot. The condo had no cross-ventilation. When I wasn’t on a Zoom call, I worked in my underwear.
I eventually bought two huge air conditioning window units, which were loud and ugly but allowed me to live and work in my condo without boiling alive in the summer.
Early in the pandemic, when I realized that I was going to be stuck at home for at least 18 more months, I decided that my first RTTPYO project would be replacing my current pieced-together, inefficient, haphazard HVAC system.
But how? The condo had no ductwork. The answer? A ductless heat pump with mini splits.
What’s a Ductless Heat Pump?
Rather than burning fuel to create heat like a traditional furnace, heat pumps work by transferring heat from one location to another. To heat a home, a heat pump extracts heat from outside the home (for example, warmth in the air), and transfers it inside the home. To cool a home, a heat pump moves the heat inside your home to the outside.
The illustration below shows how the outdoor unit, indoor mini-splits, refrigerant lines, and protective channel work together.
Ductless heat pumps have an exterior unit that supports up to five mini-split units that are installed inside the home. Compact refrigerant lines installed on the building’s exterior carry refrigerant between the interior and exterior units. These lines are run through channels called “protective line-set covers”.
Ductless Heat Pump Advantages and Disadvantages
Advantages
Because heat pumps transfer heat rather than create it, they are far more efficient than conventional heaters and are cheaper to run. I saved 30% on my electricity when I switched from my old system to mini-splits.
You can control the heating and cooling at a much more granular level in your home via each mini-split’s control panel, which can save you money if there are rooms in your home you rarely use.
Heat pumps rely on electricity rather than fossil fuel to heat a home, improving air quality.
Because the compressor is in the outside unit, you won’t hear the big “thunk” noise when it kicks in.
If something breaks, you only have to call one provider.
Disadvantages
In cold climates, heat pumps are less effective at heating a home. If that’s your scenario, buy a heat pump designed for your climate or get a backup heating system (mine was my Vornado).
Ductless heat pumps are generally more complex and require more people to install than a ducted system. With a ducted system, the crew uses the existing ductwork in the home to deliver heat and cooling. With a ductless system, the crew needs to build the system to deliver heat and cooling by attaching channels on the home’s exterior to carry the refrigerant lines from the exterior unit to each mini-split.
The upfront cost for a ductless heat pump and mini splits is expensive due to installation complexity, but I saw a 30% reduction in my electric bill because my new system was so much more efficient.
As with any HVAC system, homes that are poorly insulated, have older windows, or are drafty may cause your heat pump to be less effective.
Will a Ductless System Work in Your Home?
Whether you go ducted or ductless boils down to whether or not your home has ductwork.
The warm or cold air generated by a heat pump is distributed by ductwork—usually metal tubes that connect to the HVAC unit and transport warm or cool air to the rooms in the home. Ductwork is installed when a home is built and is located in the ceiling, attic, or walls depending on the home’s construction. If your house wasn’t built with ductwork, it’s difficult, tricky, and often impossible to install.
If your home has ductwork, you can replace the existing HVAC unit with a heat pump, and the heat pump will use the existing ductwork to distribute warm or cool air throughout your home.
If your ductwork needs to be repaired or replaced, it could cost you $12,000 or more before you even get to the heat pump. If you want to avoid the cost of repair or replacement, you can seal it off and opt for a ductless system.
If your home doesn’t have ductwork and you don’t want to add it, you’ll need to go with a ductless heat pump and mini splits.
Where Should Mini-Splits Go?
If you live in a condo (as I did), before you schedule the first appointment with a heating and cooling salesperson, talk to your HOA. You’ll need permission to install the exterior unit on the condo property and to attach the exterior channel system to the building your unit is in.
Since at that time I was running the HOA solo because the other owners refused to participate, I gave myself the go-ahead.
Next you’ll need to figure out where the exterior unit and the mini-splits are going to go. Most exterior units will support up to 5 mini-splits—if you need more than 5, you’ll need two exterior units.
The exterior unit should be placed on the ground floor, with open space around it for air flow. Installation includes the concrete pad on which the unit is placed to keep it level and off the ground.
Mini-split placement is something of an art.
They have to be installed on an exterior wall in order to be connected to the outdoor unit.
They need to be installed 6 to 8 feet above the floor, but can’t be installed above a window.
They need to be placed where they will circulate air most effectively for the room’s size and shape.
They have to be the right size to adequately heat and cool the space, which may affect placement.
Then there are the aesthetics. Sometimes the best location for a mini-split requires that a cherished item like a grandfather clock or antique highboy has to move.
And, since you cannot add a mini-split once your system is installed, you need to get that right the first time. No do-overs.
Fortunately, my mini-split locations were fairly straightforward.
A few years ago I read that the biggest regret that people had about getting a new TV was that they should have got a bigger one. It’s the same with mini splits. Go big or go home. I decided to get three—a big one for the great room and kitchen and smaller ones for the office and bedroom. That allowed me to get rid of all the wall heaters and window air conditioners.
Bliss.
If you have questions, your HVAC company’s estimator is an expert on determining optimal exterior unit and mini-split size and placement and will help you cross all those t’s and dot all those i’s. He will pass along that info to the installation crew, too.
How to Prepare for Installation Day
To prepare for the install, all I did was remove the breakables in the areas where the splits were going to be installed. I had drop cloths ready, too, but they brought their own.
A few other pieces of advice for installation day:
You’re going to need to be home all day. The installation team will ask you roughly one million questions throughout the day. In some cases they won’t be able to proceed without getting an answer from you.
If you have kids, get them out of the house for the day. The installers will be wielding dangerous equipment and playing with electricity. Relocate your kids so no one gets hurt.
It’s going to be noisy. The installers will be operating loud devices and yelling at each other all day. If you work from home, avoid scheduling conference calls, or be OK with screaming “WHAT DID YOU SAY?” multiple times on each call.
Your electricity will be off and on all day since your electrical panel will need to be reworked to accommodate the new system. Charge your laptop and phone before they arrive and don’t count on consistent WiFi. Plan on having dinner delivered that night.
Depending on your setup, the installer will probably need to access your attic space to run electrical wiring. Check with the vendor. If the installers do need it, make sure that they can get easy access and that there is space for them to navigate in the attic.
Installation Day
The day installation started, seven guys showed up at my condo:
One supervisor, complete with reciprocating saw
Two electricians
One interior mini-split installer
Three exterior installers for the exterior unit and the refrigerant lines
I had no idea so many people would be involved.
But everyone had a specific job and they did the entire install in less than a day.
When this small army arrived, several things happened in quick succession. First, the supervisor brandished a reciprocating saw, confirmed the splits’ locations, and ten minutes after arrival started cutting big holes in the corresponding exterior walls.
Disconcerting, noisy, and stinky to say the least.
The head electrician asked where the electrical panel was, turned off the electricity in the condo, and started rewiring the panel to support the exterior unit and the splits.
The first real hitch in the install occurred 30 minutes in when the electrician’s assistant asked how to get up in the attic to run the electrical lines to the exterior unit and the splits.
Dang.
While I had an attic space, I did not have access to it—I blocked it off years earlier installing a closet system in the bedroom closet.
No problem. The supervisor with his reciprocating saw was happy to open the ceiling in the office closet to get access to the attic. The drop cloths I had ready came in handy there.
But I wish I had known that the installers needed to access the attic before they got there. If you decide to go ductless, save yourself some angst and ask the estimator beforehand.
After the supervisor and his saw had ripped out the initial split opening, the interior guy unboxed the splits and worked with one of the exterior guys to position each split and affix it to the building. The exterior installer added trim to finish the outside while the interior installer did the same on the inside.
They did a fantastic job. I didn’t have to patch walls or retouch paint anywhere.
The electrician and his assistant worked alongside the rest of the crew to rewire the power panel, killing power to the awful wall heaters and “powering up” the new system. Since each split operates independently, the new wiring was fairly complicated—hence the requirement to have two electricians.
Meanwhile, outside, the exterior crew swarmed over the building installing the refrigerant and water condensation lines between the splits and the exterior unit.
Each line was encased by a channel that attached to the building. The channels protect the lines from damage and deterioration. It was extraordinarily neat and precise. Wherever possible the crew aligned the channels with the lines of the building to make the channels as unobtrusive as possible.
Eight hours later, they were done. The supervisor handed me the mini-split remotes (one for each unit) and showed me how to use the remotes and the control panels on the units.
30 minutes after that, the condo was consistently and pleasantly cool. Zoey emerged from under the bed looking for her Vornado.
Post-Installation Clean-up
The only clean up I had to do when the crew left was vacuuming up the dust remaining from cutting out the new attic access. The supervisor gave me the number of the guy they use for finish work. He came out a few days later, did his thing, and my first RTTPYO was complete.
After that, I called my handyman to come out and remove the wall heaters. Since the power to them had been switched to the splits, he simply cut them out of the wall, cut the wiring, and patched the holes. I spackled, primed, sanded, and painted the patches a week after that.
I was surprised at how much losing the wall units “uncluttered” the condo.
The day after the system was installed, several wild fires started in Oregon, which is unfortunately fairly common at the end of the summer. Thanks to my new system, I simply closed my mini-split vents to keep the air clean and cool inside my condo.
When temperatures dropped, I was happy to find that the splits did a great job heating my condo, too. And, like in the summer, my electric bill was reduced by a third—and I was warm in every room.
I was even able to put the Vornado in storage, much to Zoey’s regret.
Must-Haves for a Ductless HVAC Setup
If you’re installing (or already have) a ductless system, these are the small things that make a big difference.
1. A smart thermostat/controller —lets you adjust zones without constantly getting up
2. Surge Protector for HVAC Systems —protects a very expensive system from a very preventable problem
3. Mini Split Cleaning Kit —keeps airflow strong and prevents buildup you don’t want to think about
4. Air Quality Monitor —especially valuable in fire-prone areas
5. Wall Patch & Paint Kit —make your old wall units a distant memory
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