How To Use An Old Thermostat

If you lot're gear up to replace your old thermostat with a shiny new smart thermostat, read our half-dozen tips first to ensure a polish upgrade procedure! Nosotros learned some of these lessons "the hard way", and at present we are sharing them here and so you can learn from our mistakes!

one. Ostend your organization is "depression voltage" (24v)

The devices most commonly called "smart thermostats", such as thermostats from Nest, Ecobee, Honeywell, etc., are only compatible with "low voltage" 24v HVAC systems.

You should exist certain that your HVAC is compatible before you try to claw up a smart thermostat. "Low voltage" HVAC is oft called "central oestrus" or "central air". A skilful giveaway: you lot have ane single thermostat in your business firm (or multiples if you're multi-zone) that controls a big furnace that's tucked abroad in your basement or garage (at that place might be boosted accessories such as a heat pump, too). The wires are sparse and multi-colored. Likewise, there are lots of systems that are not compatible at all. For case, if you have a thermostat and heater pair in every room of your home, you probably have line voltage systems (which are non compatible with the popular smart thermostats available right now).

For more help, check out our detailed guide (with lots of photos!) for identifying your HVAC system type: Is your wiring compatible with a smart thermostat? Guide to depression voltage, line voltage, and more.

Besides, major manufacturers such as ecobee and Nest also offer compatibility checking tools that are piece of cake to use and will help you decide if yous can take a smart thermostat with your existing HVAC arrangement. Pop your thermostat off the wall then you tin see the wiring, and visit either of these links:

ecobee compatibility checker
Nest compatibility checker

2. Make up one's mind if you take enough wires

Just because your HVAC system is compatible doesn't necessarily mean y'all take enough wires. For most smart thermostats, including the Nest, you'll probable need a wire to plug into the C-terminal to provide continuous power to the thermostat. (Maintaining a WiFi connexion requires more than ability than your programmable or mechanical thermostat likely needed.) This may not be present on the thermostat yous're replacing. The side by side thing you should exercise, once you determine your HVAC arrangement is compatible in the first place, is to determine if y'all take a sufficient number of wires.

You'll need a C-wire for well-nigh of the pop smart thermostats available today, but in that location are many ways to bargain with the absence of a C-wire.

See our guides for more help with wiring:

C-wire guide – learn what the C-wire does
What to do if y'all don't have a C-wire – options include installing ane, using an adapter, and choosing a smart thermostat that doesn't require a C-wire

Basically, the question of "is my wiring compatible?" isn't always quickly answerable. Information technology's a good idea to determine if your wiring is compatible before you lodge a smart thermostat. You might have to wait inside your furnace or in the wall behind your current thermostat to see if you do really have enough wires and they're just non in utilize and blimp abroad, or you might take to order an adapter or new wire, or consider hiring a pro.

3. Take skillful photos of your existing thermostat wiring

Yes, this step is included in every smart thermostat installation manual but it's easy to become excited and have but one or two blurry photos (or skip this step entirely).

Your photos should be good enough to help you put your sometime thermostat back into service. Plainly, no 1 wants to think about having to put the erstwhile thermostat dorsum on the wall, just if something goes amiss during the smart thermostat installation you lot'll be glad you tin rapidly "undo" and become dorsum to what you had before. Too, if y'all end upward having to call back up they'll probable desire to know how the old 1 was wired.

Do your future self a favor and take some expert, sharp photos of your existing wiring hookups before you lot take anything apart.

four. Consider what will happen to the wall backside your existing thermostat

In some homes, swapping thermostats is no large deal – the wall is painted white and always has been, the sometime thermostat is minor and your new one is bigger – and so on.

Merely in other homes, you lot might have to take on an additional "wall repair" project in addition to the thermostat replacement. The most common problems revealed when upgrading to a smart thermostat are wallpaper impairment and mismatched pigment that won't be fully covered past the new smart thermostat.

Good news: most smart thermostats today transport with a "wall plate" for covering up the mismatched paint or harm revealed by swapping your thermostat. Chances are, the wall plate has you covered.

Wall plate that ships with Nest thermostats — The wall plate that ships with Nest thermostats is piece of cake to install – simply sandwich it between the wall and the thermostat to hide wall harm and mismatched paint that was previously hidden by your quondam thermostat.

But if you don't want to use the wall plate, you might want to think (ahead of time) about whether yous plan to repaint or repair the wall after you've put up the new smart thermostat.

5. Take a wire cutting/stripping tool on hand

Thermostat wires are sparse and easy to break, and removing your current thermostat might snap a few of the tips off. If this happens, yous'll need to make new tips suitable for inserting into the new thermostat. (See photo below – the plastic sheath has been stripped off the wire then the copper flake can be inserted into the final.)

Close up of thermostat wires going into thermostat terminals — These petty tips are piece of cake to break off – save yourself some hassle past having a wire cut and stripping tool on hand.

We use and recommend this wire stripper/cutter tool past Mulwark, simply any brand with the right approximate holes is sufficient. (You can besides cut and strip thermostat wires with a sharp scissors, but the process is much easier with the correct tool.)

MulWark wire cutters — A wire cut/stripping tool will make a DIY smart thermostat installation go a chip smoother.

vi. Decide whether you should rent a pro

Pros practise more than than just bandy an erstwhile thermostat for a new one – you could likewise bundle in any of the following piece of work:

Service your HVAC organisation
Run new wires, including a C-wire if yous demand one
Movement your thermostat to a new location
Other electrical work effectually your firm

Of the above, I can personally recommend having your thermostat moved to a better location (if needed).

We had our thermostat moved by an electrician final winter (we arranged the piece of work with a agglomeration of other electrical piece of work we needed done) and it was admittedly worth it. Our thermostat used to sit down in forepart of a sunny window and near our slider door, which was a ridiculous place for information technology: the thermostat always thought the house was warm, and then why run the heat? (Meanwhile, we froze in every other room.) So, if nosotros opened the slider door to ventilate the kitchen subsequently cooking, the thermostat thought information technology was freezing so it blasted the heat.

Our thermostat is now in the hallway that runs through the middle of our house – a much better place for information technology.

A pro is also a practiced choice if you have whatever doubts about your ability to do the job (the manufacturers say it'south DIY, but it's non always that simple in every house!) or but want it done speedily and painlessly past someone else. The peace of mind can be worth the extra expense.

Bonus tip: Don't practice the upgrade right before the "storm of the century" is expected to hit

Don't enquire how we know this i. Nosotros know you're excited – merely it's a skillful idea to expect until the weather condition is stable before you tear your electric current thermostat off the wall.