AC Installation in Ann Arbor, MI
A new air conditioner in Ann Arbor will run from June through August every year. Tell us about the house, and a licensed contractor who covers Washtenaw County will get in touch.
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Three months of real heat, and a lot of storms in between
Ann Arbor summers run June through August, with afternoons averaging 81°F. That is a short season, but it is a demanding one, and a new air conditioner needs to be sized and installed right to handle those months without straining.
Washtenaw County has seen 60 hail events and 89 damaging wind events over the past ten years. Outdoor condenser units sit exposed to that weather, so how and where one gets installed matters as much as the unit itself. Any new central air conditioner installed today also has to meet the federal efficiency minimum of 13.4 SEER2.
- 3 months
- June through August, your air conditioner is on duty
- 81°F
- the average summer afternoon it cools against
- 60 hail events
- in ten years, and hail bends the fins on outdoor coils
- 13.4 SEER2
- the federal minimum any new unit must meet
NOAA nClimDiv, 1991–2020 normals
A higher-efficiency unit would save about $30 a year to run in Washtenaw County compared with a new unit at the federal minimum.
Estimates for a typical Washtenaw County home, from EIA household energy data, Michigan fuel prices and NOAA climate normals. Your home will differ.
Michigan requires HVAC contractors to hold a state license.
The license comes from the Board of Mechanical Rules, and it belongs to the contractor, not to any single job. It says this contractor met the state's standard for the trade. It does not mean the state shows up to check this particular installation.
That check comes from the local building office instead. In most cities and counties, installing a new air conditioner needs a permit, and the work gets inspected once it's in. The license tells you the contractor is allowed to do this work. The permit and inspection tell you this installation was looked at after it was done.
Sources: Michigan Legislature · Michigan Department of Licensing and Regulatory Affairs
- What size air conditioner does my house need?
- It depends on your square footage, your ceiling height, how much shade your house gets, how well it's insulated, and how many windows it has. There's no simple chart that gets it right, because two houses the same size can need different tonnage based on those details. A contractor works this out with a load calculation, not a guess based on square footage alone. Getting the size wrong in either direction costs you. Too small and it runs constantly without keeping up. Too big and it cools the air fast but shuts off before it pulls the humidity out, leaving the house feeling damp.
- Should I replace the whole system or just the outdoor unit?
- In most cases both the outdoor unit and the indoor coil need to be replaced together. The two are matched to work at a specific efficiency and capacity. Pairing a new outdoor unit with an old indoor coil usually means it won't run the way it's rated to, and it can void the warranty on the new equipment. If your indoor coil and ductwork are recent and in good shape, a contractor can tell you whether they're compatible with newer outdoor equipment. Since 2023, new central air conditioners have to meet a federal minimum of 13.4 SEER2, which is part of why older matched pairs often can't just be split apart.
- Do HVAC contractors in Ann Arbor need a state license to work on my home?
- Yes. Michigan requires anyone doing HVAC work to hold a state license, issued by the Board of Mechanical Rules. Ask to see it before work starts. If you're not sure it's current, ask them to confirm it.