AC Installation in Madison, WI
A new air conditioner in Madison will run from June through August every year. Tell us about the house, and a licensed contractor who covers Dane County will get in touch.
Tell us about the job
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Three months of heat, and hail to think about
Madison's cooling season runs June through August, three months, with summer afternoons averaging 81°F. A new air conditioner here isn't working against extreme heat most of the year, but it still needs to be sized right for those three months.
The outdoor unit sits outside year round, and Dane County has seen 140 hail events and 128 damaging wind events over the past ten years, with hailstones as large as 2.5 inches. Where that unit goes and how it's protected matters. 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
- 140 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
Going above the federal minimum saves little here, about $20 a year.
Estimates for a typical Dane County home, from EIA household energy data, Wisconsin fuel prices and NOAA climate normals. Your home will differ.
Wisconsin requires contractors to register with the state.
That registration puts the business on file with the Department of Safety and Professional Services. Nobody is tested to get it, and the state does not check the work behind it. Counties and cities in Wisconsin cannot require their own HVAC license either, so this registration is what exists at the state level for a contractor doing this work.
For an air conditioner installation, the protection that matters comes from the local building office instead. In most cities and counties, putting in a new air conditioner needs a permit and a final inspection once the work is done. That inspection is what checks the unit was installed correctly. The state registration does not cover that.
Sources: Wisconsin Legislative Reference Bureau · Wisconsin Department of Safety and Professional Services
- 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 works through your square footage, your windows, your insulation, and how many people are usually home, and comes out with a number in tons. An oversized unit cools the air fast but shuts off before it pulls the moisture out, so the house feels clammy. An undersized one runs constantly on your hottest afternoons and still can't keep up. With summer highs here averaging 81°F, getting the size right matters more than the brand or the price tag.
- Should I replace the whole system or just the outdoor unit?
- If your indoor coil and outdoor unit were installed together, replace them together. The coil and the outdoor unit are matched to work at a specific capacity and efficiency, and pairing a new outdoor unit with an old coil usually means the system never hits the performance either part was built for. It can also void the manufacturer's warranty on the new equipment. A contractor can check the age and condition of what's inside before you decide, since a coil that still has years left changes the math.
- Do HVAC contractors in Madison need a state license to work on my home?
- Wisconsin requires HVAC contractors to register with the state, through the Department of Safety and Professional Services. Ask to see this before any work starts on your home. It's a straightforward way to confirm the person you're hiring is who they say they are.