A Homeowner’s Guide to Choosing a Replacement Thermostat

In the market for a new thermostat?

To help you navigate the wide world of thermostats, we’ve created a step-by-step guide to help you choose the right replacement thermostat for your home.

Choosing a replacement thermostat involves 3 easy steps:

We often get this question from Arizona homeowners: “What kind of thermostat do I need?”

In this section, we’ll go into the 3 main types of thermostats, and discuss their pros and cons.

Also called “mechanical” or “non-programmable” thermostats, manual thermostats are the most basic type of thermostat you can buy. You must manually adjust it to turn your HVAC system on and off and control the temperature.

You can buy 2 types of manual thermostats:

• Digital, which use arrow buttons to control temperature
• Analog, which has a dial to change temperature

The downside to manual thermostats is that some models aren’t the most precise when it comes to temperature control. In fact, some manual thermostats have about a +/- 3° differential, while other types of thermostats only have a +/- 1° differential.

Programmable thermostats do just what their name suggests: they can be programmed to save you money on your energy bills. In fact, according to Energy.gov, programmable thermostats can save you up to $180 per year in lower energy bills.

For example, if you’re at work 5 days a week for 8 hours, that’s 40 hours every week during which you can dial back your AC or heating system to save you money. And sure, you can turn your HVAC system off with a manual thermostat, but that means you’ll always come home to uncomfortable temperatures.

A programmable thermostat solves this issue by telling your HVAC system when to turn on/off and to what temperature, so you don’t have to do it manually.

Here’s how it works:

If you leave the house at 8 am and don’t come back until 6 pm, you can program your thermostat to automatically raise or lower (depending on the season) your home’s temperature by 10° right at 8 am. Then, you can set it to automatically return to comfortable temperatures at 5:30 pm so that the house is comfortable by the time you get home.

Smart thermostats are programmable thermostats taken to the next level of connectivity and comfort. You can control these thermostats from your computer, tablet or phone which means you can adjust your home’s temperature remotely.

Though they are the most expensive, these thermostats have the best comfort features and also save you money every month on your utility bills.

Some comfort features you can find on smart (and some programmable thermostats) include:

• Touch screen displays
• Voice instructions and notifications
• Dirty air filter alerts
• Multiple programmable schedules (weekday, weekend, vacation, etc.)
• Schedule “learning” capabilities (where the thermostat learns your daily schedule automatically instead of you having to program it)

Once you determine the kind of thermostat you need, you’ll want to be sure that you pick a specific model that’s compatible with your HVAC system.

To make sure a thermostat is compatible with your system, check that it can work with:

1. Your system’s specific voltage
2. The location on the wall
3. The # of heating/cooling stages your system has

Let’s go into more detail about each of these points...

Your HVAC system either is a low voltage, millivolt or high voltage system. You’ll need to get a thermostat that is compatible with your system’s voltage requirements.

Most thermostats work with low voltage systems. And the good news is, unless you have wall/floor heaters or an electric baseboard heating system, you most likely have a low voltage system because they are the most common.

How to confirm your thermostat works with a low voltage system:

Look at the specs on the thermostat box or manufacturer label. If you’re looking online, look for the words “low voltage,” as seen in the screenshot below:

Note: If you have wall/floor heaters or an electric baseboard heating system, you either have a millivolt or high voltage system, respectively. You’ll want to contact a professional for help choosing a thermostat that works with those systems.

Don’t forget to verify that the new thermostat will fit in the same location so you don’t have to mess with rewiring. Also, keep in mind that if your home is zoned, each zone has its own thermostat so you’ll need to purchase multiple thermostats.

Not comfortable doing these steps yourself? Contact a professional to make sure your new thermostat is compatible with your system.

“Stages” refers to how many speeds your AC or heating system can run.

Your HVAC system will fall into 1 of the following categories:

• 1-stage = the system works at full speed, or off (like an ON/OFF switch)
• 2-stage = the system works at a LOW or HIGH speed
• Variable speed = the system can ramp up or down its cooling/heating levels depending on what’s needed at any moment

The bottom line is that you’ll need to confirm that your thermostat’s wiring is compatible with the number of stages your HVAC system has.

Since this step requires you to “read” your current thermostat wiring, it’s best to have a professional handle this for you.

The easiest (and safest) way to install your thermostat is to have a professional do it for you.

An improperly installed thermostat (due to a DIY attempt) can result in:

• HVAC system malfunctions
• Lowered comfort (improper wiring can even leave you without cold/warm air)
• Expensive repairs
• Unnecessarily high monthly energy bills

Hiring a pro guarantees that your thermostat will work with your system and that you won’t run into any problems down the road.