The house ran on oil heat with no air conditioning anywhere. Pespisa added a 5-zone Mitsubishi system for quiet, room-by-room cooling, plus efficient heat on milder days.
Air conditioning in every room changed the way this Wilmington, MA home could be used during the summer. The house had reliable oil heat for winter, but once the weather turned warm, there was no dedicated cooling system anywhere in the home.
The upstairs bedrooms took the worst of it. Like many second-floor rooms in older Massachusetts homes, they held heat once summer set in. Fans and open windows could only do so much, and adding traditional central AC would have required ductwork the house did not already have.
Instead of tearing into the home to add ducts, Pespisa installed a 5-zone Mitsubishi mini split system that put cooling exactly where the family needed it. One outdoor unit feeds five indoor heads, each with its own control, so the home can be cooled room by room. On milder spring and fall days, the system can also provide efficient heat, helping take some of the load off the oil burner.
Project Snapshot
| LOCATION | Wilmington, MA |
| APPLICATION | Residential, add cooling to an oil-heated home |
| SYSTEM | Mitsubishi 5-zone ductless mini split heat pump |
| OUTDOOR UNIT | Mitsubishi MXZ-5D36NL, 36,000 BTU, 3 tons |
| INDOOR UNIT | 2x MSZ-GX06NL, 2x MFZ-KX09NL, 1x MSZ-GX12NL |
| REFRIGERANT | R-454B |
| CONTROLS | 3 Ecobee smart thermostats |
| ELECTRICAL | New 30-amp dedicated circuit to outdoor unit |
| ZONES | 5 |
| GOAL | Add air conditioning in every room that needed it without new ductwork |
The Challenge: Oil Heat, and No Way to Cool the House
The home was comfortable in winter, but difficult to live in once summer arrived.
It had oil heat and not a single air conditioner. When temperatures climbed, the only options were fans and open windows. That left the family without real cooling in the rooms where they needed it most.
The second-floor bedrooms were especially uncomfortable. As heat rose through the house, the upstairs rooms became the hardest to cool, which made summer nights less restful.
Traditional central AC was not the right answer for this home. Adding it would have required ductwork the house did not have, turning the project into a much larger and more invasive renovation.
There was also a seasonal comfort issue. On mild spring and fall days, running the oil heat for a little warmth was more than the house actually needed. The homeowner wanted a solution that could cool the home in summer and offer efficient heat when full oil heat was not necessary.
The goal was clear: add air conditioning in every room that needed it without tearing the house apart to get it. For this homeowner, air conditioning in every room was not about luxury. It was about making the house livable during the warmest parts of the year.
Our Solution: A Five-Zone Mitsubishi System, One Outdoor Unit Feeding Five Rooms
Pespisa designed and installed a Mitsubishi multi-zone mini split system built around the home’s actual layout.
The system uses one outdoor heat pump to run five indoor units. Each indoor head was selected to fit the room it serves, giving the family targeted comfort instead of a one-size-fits-all cooling setup.
The outdoor unit:
- Mitsubishi MXZ-5D36NL multi-zone heat pump
- 36,000 BTU
- 3 tons
- Runs on R-454B refrigerant
Five indoor heads, matched to each space:
- Two MSZ-GX06NL wall units, 6,000 BTU, for the first-floor bedrooms
- Two MFZ-KX09NL floor-mounted units, 9,000 BTU, for the second-floor bedrooms
- One MSZ-GX12NL wall unit, 12,000 BTU, for the TV room
The rest of the install included:
- A new 30-amp circuit run from the panel to the outdoor unit
- Outdoor unit set on a composite pad and wall stand
- White line-hide covering the refrigerant lines for a clean exterior look
- Three Ecobee smart thermostats
Each zone runs independently. A bedroom in use can be cooled while an empty room stays off. That gives the family comfort where they want it and avoids spending energy where they do not.
Why This Design Was the Right Fit
A ductless system was the right call for a house like this one.
Because the home did not have existing ductwork, a ductless mini split avoided the need to open ceilings, sacrifice closet space, or build new duct runs through the house. The indoor heads connect back to the outdoor unit through small line sets, making the installation much less invasive than adding traditional central AC.
The five-zone design also gave the family room-by-room control. This mattered because the home did not need the same level of cooling everywhere at the same time. The upstairs bedrooms could run cool at night while the rest of the house sat idle.
Quiet operation was another important part of the design. Mini split heads run quietly, which makes them a strong fit for bedrooms and a TV room where comfort should not come with extra noise.
The system also gave the home a smarter way to handle mild-weather heating. On spring and fall days, the heat pump can warm the rooms instead of firing the oil burner. That helps reduce oil use during the shoulder seasons while leaving the oil system available for the coldest stretches of winter.
The Result: Room-by-Room Comfort Without New Ductwork
The family now has cooling in every room that needed it, controlled zone by zone, from a system that went in without any new ductwork.
The hot upstairs bedrooms now have dedicated cooling. The first-floor bedrooms and TV room also have their own indoor units, giving the homeowner more control over the spaces used most often.
The project delivered:
- Air conditioning in every room that needed it, including the hot upstairs bedrooms
- Five independent comfort zones
- Quiet indoor heads in the bedrooms and TV room
- Efficient heat pump warmth on milder days
- Less reliance on the oil burner during spring and fall
- A clean exterior with refrigerant lines tucked into white line-hide
- Cooling added without installing new ductwork
For this Wilmington home, the upgrade was not just about adding AC. It was about giving the family a practical way to use the whole house more comfortably through summer, while also adding efficient heat for the milder parts of the year.
Equipment Used for This Wilmington, MA Mini Split Installation
| Application | Residential, add cooling to an oil-heated home |
| System | Mitsubishi 5-zone ductless mini split heat pump |
| Outdoor unit | MXZ-5D36NL, 36,000 BTU (3 tons) |
| Indoor units | 2x MSZ-GX06NL (6K), 2x MFZ-KX09NL floor (9K), 1x MSZ-GX12NL (12K) |
| Refrigerant | R-454B |
| Controls | 3x Ecobee smart thermostat |
| Electrical | New 30-amp dedicated circuit to outdoor unit |
| Zones | 5 |
| Location | Wilmington, MA |
Got a House With No AC, or Rooms You Just Can’t Cool?
If your home runs on oil, gas, or electric heat and has no air conditioning, a ductless mini split can add cooling room by room without the mess of new ductwork.
Whether you need to cool upstairs bedrooms, a TV room, or bring air conditioning in every room that needs it, Pespisa can design a Mitsubishi system around the way your home is actually used.