The short answer
Right size, every time. An oversized AC makes the house cold and clammy.
An air conditioner does two jobs: it drops the temperature and it pulls moisture out of the air. An oversized one hits the temperature fast, shuts off, and never runs long enough to do the second job. You end up cool, damp and uncomfortable, with a machine that switches on and off all day.
Side by side
Both sides, plainly, including what each one is bad at.
Right size
Sized to your actual house, so it runs longer and steadier.
- Pulls the damp out of the air properly, so the house feels fresh
- Even temperatures instead of cold blasts and warm gaps
- Runs quieter, because it is not slamming on and off
- Lasts longer — most wear happens at start-up
- Costs less to buy and less to run
- On a record-breaking day it works hard and takes its time
- It means someone actually has to measure your house first
Oversized
More cooling than the house needs, on the theory that more is safer.
- Drops the thermostat number quickly
- Feels reassuring when you are picking equipment
- The house ends up cold and clammy, because the damp never gets removed
- Switches on and off constantly, which is the fastest way to wear a system out
- Costs more to buy and more to run
- Noisier, with a noticeable blast every time it kicks in
- Uneven rooms, because it never runs long enough to even the house out
Which one is you?
Right size is right if…
You want the house to feel comfortable rather than just read a number on a wall. This is what a proper load calculation is for — measuring your rooms, windows, insulation and orientation instead of guessing from square footage.
Slightly larger is defensible if…
You are about to add a room, finish a basement, or replace old single-pane windows in a way that changes the house. Even then it is one step up, deliberately, not two. Nobody should be guessing.
Getting quotes with different sizes on them?
That usually means somebody guessed. We will measure the house and tell you the size it actually needs, and why.
Get My Upfront Quote60 seconds online · or call (206) 486-6373
What sizing is worth
Typical industry ranges for Western Washington — not a quote. Your exact price comes upfront, before any work starts, and you approve it first.
Why homeowners hand it to us
- You approve the price first. Upfront quote before a single screw turns.
- Same-day service. Book in a minute, hear from a tech within 1 business hour.
- 500+ jobs done by 4.9★ rated, professional technicians.
- Fixed right, guaranteed. If it’s not right, we make it right.
Quick answers
What does a "ton" mean on an air conditioner?
It is just the unit of cooling capacity, nothing to do with weight. A typical Puget Sound home lands somewhere between two and four tons. What matters is that the number comes from measuring your house, not from a rule of thumb.
Why does an oversized AC make the house humid?
Removing moisture takes running time. A system that satisfies the thermostat in eight minutes and shuts off has not had time to wring the damp out of the air. You get a house that is cool but sticky, which most people describe as feeling colder and worse.
My AC turns on and off constantly. Is it oversized?
It might be, and that is one of the common causes. It can also be a dirty filter, a low refrigerant charge or a failing part. Worth having someone look before assuming the worst.
How do you work out the right size?
By measuring: the rooms, the windows and which way they face, the insulation, the ceiling heights and how leaky the house is. Two identical-looking houses on the same street can genuinely need different sizes.
Is the same true for a furnace or heat pump?
Yes, and for the same reason. Oversized heating gives you hot blasts and cold gaps, and it wears the equipment out faster. Right-sized is steadier and more comfortable in both directions.
Get the size right the first time.
Book a visit. We measure the house, explain the number we get, and give you the price upfront.
Get My Upfront Quote60 seconds online · or call (206) 486-6373
More comparisons: High efficiency vs standard · Central air vs window units · Heat pump vs AC · all comparisons