AC Replacement in Boise, ID
A new system is the biggest single mechanical purchase most Boise homeowners make, and it is usually decided in the week it breaks. This page is the homework, so you are not doing it while the house is at 88 degrees.
What a new system costs in Boise, installed
| System | Typical Boise cost | Notes |
|---|---|---|
| AC only, single-stage, existing ducts | $5,400-7,600 | like-for-like swap |
| AC + matched coil and air handler | $6,900-8,900 | the common real answer |
| High-efficiency two-stage or variable | $9,200-11,800 | quieter, better on humidity |
| Heat pump, whole-house | $8,400-14,000 | genuinely viable in Boise winters |
| Swamp cooler to central air conversion | $6,800-14,500 | ductwork is the variable |
| Duct repair or rework | add $900-4,800 | often the real cause of hot rooms |
| Whole-house media filtration | add $450-1,600 | wildfire smoke season |
| Electrical panel or circuit upgrade | add $600-2,800 | older homes |
If you are still on a swamp cooler
This is the Boise-specific decision, and it is worth getting right because it is easy to spend the money badly. Evaporative coolers work here in a way they do not in humid climates - the dry air is exactly what they need. They are also cheap to run and simple to fix.
Two things have changed the calculation. Monsoon weeks in July and August push the humidity up enough that a swamp cooler stops cooling and starts making the house clammy. And wildfire smoke - a swamp cooler pulls outside air in through a wet pad, which means on a bad smoke day it is bringing the smoke with it. A sealed refrigerant system with proper filtration is the only setup that solves that.
The catch is that the conversion is not just a new box outside. Most swamp cooler houses have either no ducts or ducts sized for a completely different airflow, and that is why the range runs from $6,800 to $14,500. Get the ductwork assessed before you accept any number.
Filtration Stopped Being Optional Here
Boise summers now routinely include stretches of heavy wildfire smoke, and that changed what a good system looks like. A one-inch filter in a return grille does very little against fine particulate.
A four- or five-inch media cabinet, or an electronic air cleaner, is a $450-1,600 line on a new install and it is much cheaper to add while the system is being replaced than as a separate job later. If a quote does not mention filtration at all, ask about it before you compare prices.
What a Boise replacement quote usually does and does not cover
Included
- The condenser, indoor coil and matched air handler or furnace coil
- Refrigerant line set connection, evacuation and charge
- Removal and disposal of the old equipment
- New thermostat and basic commissioning with measured airflow
- Manufacturer parts warranty and the contractor's labour warranty
Not included
- Duct repair, sealing or resizing - very often the reason a room never cools
- Electrical panel or circuit upgrades on older homes
- A concrete or composite pad for the outdoor unit, on some quotes
- Permits and inspection, where the City of Boise or Ada County requires them
- Whole-house filtration, unless it is a separate line you asked for
Sizing matters more than the brand on the box
The single most common mistake in residential HVAC is buying a system that is too big, and it happens because oversizing is the safe-sounding choice. An oversized air conditioner cools the air fast, shuts off, and never runs long enough to do the rest of its job. You get cold spots, short cycling and a compressor that wears out early.
The fix is a load calculation - a Manual J or equivalent - based on your actual square footage, insulation, windows and orientation, not on what was there before. Ask whether the quote is based on one. A contractor who has done the calculation will tell you happily; one who has not will change the subject to brands.
How to compare three quotes that look the same
- Fix the specification first: capacity in tons, SEER2 rating, single-stage or two-stage, and what the indoor coil is. Then compare prices.
- Ask whether the size came from a load calculation or from matching the old unit. That one question separates the quotes more than anything else.
- Ask what the quote assumes about your ducts, and what happens if they turn out to be undersized. A stated allowance beats a surprise.
- Separate the manufacturer parts warranty from the contractor's labour warranty, and get both in writing with their lengths.
- Ask for the total installed price with permits included. A verbal number on a doorstep is not a quote.
When replacing is the wrong answer
Worth saying plainly, because we have nothing to gain from you buying a system you do not need. An eight-year-old unit that needs a $320 capacitor and a clean is a repair, not a replacement. If someone opens with replacement on a system that age, ask them to price the repair as well and put both on paper.
Get a written quote for a new system
Tell us the square footage, roughly how old the current system is, and whether you have ducts or a swamp cooler. We will match you with one vetted Treasure Valley contractor who quotes in writing. No charge for the match, no obligation, and we do not hand your number to four companies who will all call you.
Or call (208) 330-2375
Common questions
Should I convert from a swamp cooler to central air?
It depends on your ducts more than on the cooler. Swamp coolers genuinely work in Boise's dry air, but they fail in monsoon humidity and they cannot filter wildfire smoke. Get the ductwork assessed first - that is what moves the price from $6,800 to $14,500.
Is a heat pump worth considering in Boise?
More than in colder markets. Boise winters have cold snaps but are mild enough that a modern heat pump holds its efficiency most of the season, and it replaces both halves of the system at once. Ask for it to be quoted alongside straight AC so you can see the difference.
What SEER2 rating should I buy?
The efficiency premium pays back faster the longer your cooling season, and Boise's is moderate. For most homes here the mid-range is the sweet spot; the top tier makes more sense if you are staying long-term or the house is hard to cool.
How long does a replacement take?
A like-for-like swap is usually one day. Duct rework or a swamp cooler conversion runs two to four days depending on access.
Why does the range go from $5,400 to over $14,000?
Because it covers a basic like-for-like AC swap at one end, and a full swamp-cooler-to-ducted-heat-pump conversion at the other. The table above shows which row you are in.