Climate Zone & Why It Matters

Some Americans barely experience a hot day. Others never see snow. Those who are particularly unlucky know exactly what high humidity feels like in summer and winter. What we're getting at is that life can be very different depending upon the climate zone in which you live. Different climes requires different clothes, habits, and practices. So when it comes to investing in a system for home air comfort, don't forget about it.

Broadly speaking, the United States is divided into eight climate regions. In the below image from the US Department of Energy, you can see the seven regions that comprise the Continental US. The eighth region, a sub-arctic zone, is found only in Alaska. Hawaii is in their own zone. It's called the Everything-is-Fine-Here-Because-It's-Hawaii Zone.

US climate zones

Climate Zone Features

Zone 1: Hot-Humid

Folks in Climate Zone 1 get to enjoy at least 20 inches of rain each year, and all the wonderful humidity that comes with it. They get long summer days with plenty of heat. When it comes to cold weather, they barely know what it is.

What kind of HVAC system should you have? Get a heat pump and nothing else. It will never ever get cold enough for you to need anything more than that.

Zone 2: Mixed-Humid

The Mixed-Humid Climate Zone 2 really gets the best of both worlds. No only do they get that solid 20+ inches of rain, but they get lots and lots of hot days. The northerly regions even get to enjoy ice storms and miserable, wet winters.

What kind of HVAC system should you have? A new high performance heat pump can do everything you need. Lots of people in this zone have gas furnaces, but most won't need them. If you really do need one, at least go heat pump gas and electric. Don't use that gas unless you gotta.

Zone 3: Hot-Dry

The Hot-Dry Climate Zone 3 is, well, a desert. They get minimal precipitation, and a lot of heat. The only time there was ice here was during the last Ice Age.

What kind of HVAC system should you have? A heat pump. Maybe a humidifier, but that's it.

Zone 4: Mixed-Dry

Climate Zone 4 is Mixed-Dry and just wonky. They don't get a lot of annual precipitation, so they don't have to worry about high summer humidity or tons of snow. But it can get quite hot in summer and reasonably cold in winter.

What kind of HVAC system should you have? Get a heat pump with an auxiliary heat kit. And like Zone 3, a whole home humidifier might not be a bad idea either. You shouldn't need a furnace unless you're right on the boundary.

Zone 5: Cold

The Cold Climate Zone 5 is the North (and a lot of the West). They have summer, but it never gets too brutal. They also have long, snowy, cold winters with lots of below zero days, wind chill, and polar vortexes.

What kind of HVAC system should you have? You folks need an air conditioner for summer and a gas furnace for winter. Because your winter is no joke.

Zone 6: Very-Cold

Do you live in Very-Cold Climate Zone 6? If so, you are among very few Americans who get to enjoy basically a three day summer weekend and Eternal Winter. So, congratulations. You should really take some time off to drive to Michigan. It's positively balmy by comparison.

What kind of HVAC system should you have? You probably don't need an air conditioner. Seriously, you'll be fine. Get a furnace though, if you want to live.

Zone 7: Subarctic

Only Alaskans live in a sub-arctic climate. Well, Alaskans and Canadians. Who are basically like 59% American, so it sort of counts. In any case, it is cold in Climate Zone 7.

What kind of HVAC system should you have? Definitely not an air conditioner. Definitely a furnace. And a really good furnace with a good warranty. Because may God have mercy on you if it breaks down.

Zone 8: Marine

The entirety of the West Coast is the Marine Climate Zone 8. Warm ocean currents and breezes mean that it usually stays relatively comfortable for a lot of year. It never gets too miserably hot in summer or too brutally cold in winter. Basically, it's the best place to live in terms of climate zone which does go a long way to explaining California.

What kind of HVAC system should you have? Do you people really need anything? Gah! Okay, well, maybe an energy efficient heat pump. Get a heat strip if you're really in the northerly part.

Climate Zone Cooling Impact

Cooling energy efficiency is typically measured according to Seasonal Energy Efficiency Ratio (SEER). There is a lot of math behind what that means, but it is fundamentally easy to understand. Because the main fundamental is that the higher the SEER, the more efficient the air conditioner or heat pump.

In northern states, the Midwest, the mountain states, and the Pacific Northwest, the federal minimum is 13 SEER. Which means that if you live in Portland, you can install a 13 SEER air conditioner.

The Federal standard is much higher in Florida, Texas, New Mexico, and pretty much anywhere else that really needs air conditioning.


The warmer the climate zone in which you live, the more you are going to use that air conditioner. Which would be fine if it was just you with an inefficient air conditioner, but it wouldn't be. It would be everybody. So making everybody have more efficient systems in hot zones means a gigantic amount of saved energy.

By contrast, Portland and places like it never get that hot. Which means that even when they do run their relatively inefficient air conditioners, they're not really using too much energy.

North, Southeast, and Southwest

To keep it simple, the Department of Energy has divided the country into three big regions when it comes to air conditioner efficiency. There is the North, the Southeast, and the Southwest.

The North can do pretty much whatever they want. Any new heat pump or air conditioner they install can be as low as 13 SEER. The Southeast is more strict. They can only install 14 SEER equipment. The Southwest, where all that desert is located, is even more strict. Their equipment has to be 14 SEER, but it also has to be 11.7 EER or better depending on size.

So for you Floridians who just found a great deal online for a new 13 SEER air conditioner, don't get too excited. That 13 SEER unit is about as useful to you as a wooden nickel.

But All is Not Lost

Let’s talk about dollars. 14 SEER units are more expensive to buy. But the good news is their superior efficiency means they do cost less to run. Since those of us who have to buy them will run them a lot, the increased efficiency can pay off over time.

Upgrading from 13 SEER to 14 SEER means your air conditioner or heat pump is roughly 7% more efficient. If you spend $100 on air conditioning each month, you would save about $70 per year. Which over a decade is a not-small amount of money. Obviously, if you spend even more than that each month, and some people do, the savings can really start to add up.

In the long term, you can recoup real dollar value thanks to the extra efficiency. Plus, large groups of people investing in energy efficiency products helps us keep energy prices low overall.

How Does Climate Zone Impact Heating?

If you are thinking that the Department of Energy probably has higher efficiency standards for a northern climate zone than a southern one, then you are actually not correct. At least not yet, but you will be eventually.

As of 2015, the DOE finalized the standard for gas furnaces at 80% Annual Fuel Utilization Efficiency (AFUE). As with SEER, the higher the AFUE, the better. The Department had further proposed increasing the efficiency requirement for the North to 90% AFUE. However, lobbyists got them to hold off on that standard. As of today the DOE has yet to issue a revised standard, but they inevitably will do so.

Final Thoughts

Climate and weather play an obvious, unalterable role in our lives. But that doesn't mean we have to be miserable. Invest in the right heating and cooling technology to ensure your home is as comfortable as modern technology will allow. As always, we're here to help when you have questions about the best way to beat Mother Nature in your climate zone.

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