Massachusetts HVAC Pros
An outdoor air conditioning condenser unit positioned on a concrete pad next to a blue-sided house, surrounded by green shrubs and flowering hydrangeas at sunset.

AC Installation in Cambridge, MA

A new air conditioner in Cambridge will run from July through August every year. Tell us about the house, and a licensed contractor who covers Middlesex County will get in touch.

Tell us about the job

It takes about a minute.

Step 1 of 3: Equipment
Aerial view of a square outdoor air conditioning condenser unit on a concrete pad beside a house wall with a sliding glass door.

Two months of real heat is what your new AC has to handle

Cambridge only asks for cooling in July and August, but those afternoons average 81°F, and a new system has to be sized to keep up on the hottest of them, not just the mild ones. Get the size wrong and it either runs constantly trying to catch up or short cycles without pulling the humidity down.

Any new central air conditioner installed today has to meet a federal minimum of 13.4 SEER2. That is the efficiency floor, not a sign of what size or brand fits your house. A contractor still has to work that out from your home.

2 months
July through August, your air conditioner is on duty
81°F
the average summer afternoon it cools against
47 hail events
in ten years, and hail bends the fins on outdoor coils
13.4 SEER2
the federal minimum any new unit must meet
Isometric cutaway illustration of a small home interior with furniture and ducting, showing an indoor air handler connected by lines to an outdoor condenser unit on a pad.
Your air conditioner works hardest from July through August.

NOAA nClimDiv, 1991–2020 normals

Overhead view of an outdoor AC condenser unit on a concrete pad next to a house with a dark shingle roof.

A higher-efficiency unit would save about $40 a year to run in Middlesex County compared with a new unit at the federal minimum.

  • A higher-efficiency unit$310 a year
  • A new unit at the federal minimum, 13.4 SEER2$350 a year

Estimates for a typical Middlesex County home, from EIA household energy data, Massachusetts fuel prices and NOAA climate normals. Your home will differ.

What size air conditioner does my house need?
The right size comes from a load calculation, not a rule of thumb based on square footage. A contractor looks at your home's insulation, window area, ceiling height, and layout to figure out how much heat needs to move out on a hot afternoon. An oversized unit cools the air fast but shuts off before it pulls the humidity out, so rooms feel clammy. An undersized one runs constantly and still can't keep up when it's 81 and sunny. Get a contractor to run the calculation rather than matching the number stamped on the old unit.
Should I replace the whole system or just the outdoor unit?
If the indoor coil wasn't matched with the outdoor unit originally, or if it's old, replacing just the outdoor unit usually isn't a good idea. The coil and the outdoor unit are engineered to work together, and pairing new outdoor equipment with an aging coil can mean it never reaches its rated efficiency and may wear out sooner. A contractor can check whether your existing coil is compatible with newer outdoor equipment before you decide.
Do HVAC contractors in Cambridge need a state license to work on my home?
Ask to see a contractor's license number before work starts, and check that it's current. A licensed contractor also carries the insurance that protects you if something goes wrong during installation. If you're not sure what to ask for, request the license and insurance details up front rather than after the work begins.
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