What is the difference between a 1 stage and 2 stage thermostat?

Thermostats are an important part of any HVAC (heating, ventilation and air conditioning) system, allowing you to control the temperature in your home or building. There are two main types of thermostats – 1 stage and 2 stage. Both work to regulate temperature, but in different ways.

In this article we’ll take a closer look at how 1 stage and 2 stage thermostats work, their key differences, and help you decide which type might be best for your needs. Understanding thermostat stages can ensure you choose the right model and set it up properly to maximize efficiency and comfort.

What is a 1 Stage Thermostat?

A 1 stage thermostat is the simpler of the two types. It operates with an on/off cycle, turning your HVAC system on when the temperature reaches one setpoint, and off once it reaches another setpoint.

For example, you could set a 1 stage thermostat to 68°F for heat mode. Once the temperature drops below 68°, it will turn on the heat. It will continue heating until the temperature climbs above 68° again, at which point it will turn the heat off.

The setpoints have a preset deadband, usually around 2 degrees, to prevent the system from constantly turning on and off. So in the example above, if set to 68°F, the heat would turn on at 67°F and off at 69°F.

Key Features of 1 Stage Thermostats

– Simple on/off operation
– Usually just one temperature control (heat/cool setpoints)
– Wider temperature swing around setpoint (less precise)
– Compatible with single stage HVAC systems
– Lower cost than 2 stage models

One stage thermostats are a very basic, affordable option suitable for many homes and smaller commercial spaces with single stage heating and cooling systems. Their main drawback is less advanced temperature control.

What is a 2 Stage Thermostat?

A 2 stage thermostat offers a bit more complexity in its operation. As the name suggests, it can control HVAC systems with two stages or cycles of heating and cooling.

The key difference is that a 2 stage thermostat can activate just one stage, or both stages together, depending on how far the temperature is from the setpoint. This allows for more incremental temperature control.

For example, you could have a 2 stage heat pump with the following two stages:

– Stage 1: 60% heating capacity
– Stage 2: 100% heating capacity

If the temperature drops a degree or two below the setpoint, the thermostat will activate Stage 1 heating to gently raise it back up. If it drops significantly below the setpoint, the thermostat will activate Stage 1 and 2 heating together for faster temperature rise.

Two stage cooling works the same way in reverse – Stage 1 to gently lower temperature, and Stage 1 + 2 together if it rises significantly above the setpoint.

Key Features of 2 Stage Thermostats

– Controls 2 stage HVAC systems
– More precise temperature control
– Usually has two setpoints for heat/cool modes
– Provides gradual staging of heating and cooling
– Reduces temperature swings and saves energy
– More expensive than single stage models

The main advantage of a 2 stage thermostat is the improved temperature control and energy savings. It will maintain a tighter temperature range around the setpoint and reduce temperature swings throughout the day.

Key Differences Between 1 Stage and 2 Stage Thermostats

Now that we’ve covered the basics of how each type operates, let’s summarize some of the key differences:

Temperature Control

1 stage thermostats only turn the HVAC system fully on or off. This results in wider temperature swings around the setpoint, such as +/- 3°F.

2 stage thermostats can gradually ramp up heating or cooling as needed, providing more precision around the setpoint, such as +/- 1°F.

System Compatibility

1 stage thermostats are compatible with single stage HVAC systems. 2 stage thermostats are needed to control variable-capacity systems properly.

Efficiency

2 stage systems are generally more energy efficient, since they only use as much heating or cooling as needed to maintain the setpoint. A 1 stage system has to run at 100% capacity even for small temperature adjustments.

Setpoints

Most 1 stage thermostats have a single setpoint for heat and cool modes. 2 stage models often have two setpoints to activate the different stages.

Complexity

1 stage thermostats are simpler to operate with less user adjustment needed. 2 stage thermostats offer more customization but can require more learning to set up properly.

Cost

Single stage thermostats tend to be more affordable, often under $50. Two stage thermostat costs start around $100 and go up from there for advanced models.

Features

Higher end 2 stage thermostats offer more advanced comfort features like humidity control, smart scheduling and remote access. Most 1 stage models just provide basic temperature control.

When Should You Choose a 1 Stage Thermostat?

Here are some situations where a basic 1 stage thermostat makes the most sense:

– You have a single stage heating and cooling system – A 1 stage thermostat is the most compatible match for controlling systems that only have a single heating and cooling stage. The 2 stage model won’t provide additional benefit.

– You want basic temperature control – If you don’t require the greater precision of a 2 stage thermostat, a simple 1 stage provides affordable set-and-forget operation.

– Your system is older – Many older HVAC systems were designed to work with 1 stage thermostats. Upgrading to 2 stage models likely won’t offer substantial efficiency improvements.

– You are on a budget – For under $50, a 1 stage thermostat provides reliable temperature control without expensive bells and whistles you may not need.

– You live in a mild climate – In areas that don’t experience major swings between heating and cooling seasons, a 1 stage thermostat is often sufficient to maintain comfort.

– Using it occasionally – For a secondary space like a garage or vacation home that doesn’t require extensive climate control, a 1 stage model keeps costs down.

– You prefer simplicity – Many homeowners and tenants appreciate the straightforward operation of an entry-level 1 stage thermostat. They are intuitive and don’t require much adjustment.

When Should You Choose a 2 Stage Thermostat?

Here are situations where investing in a more advanced 2 stage thermostat is advisable:

– You have a variable-capacity HVAC system – To maximize comfort and efficiency from a multi-stage system, it needs a thermostat capable of controlling the different stages and modulating.

– Tight temperature control is a priority – Keeping your home or office temperature precisely maintained around the clock requires a 2 stage thermostat.

– You want better efficiency – Staged heating and cooling cycles waste less energy than full-blast on/off operation from 1 stage models.

– Your home has hot/cold spots – Multi-stage operation helps provide even heating and cooling throughout the whole house.

– You want advanced features – Top models provide smart scheduling, remote access, moisture control and integrations to take climate control to the next level.

– You use zones in a commercial building – Precise multi-zone thermostats require at least 2 stages to independently control different areas.

– You live in an extreme climate – Very hot or cold regions benefit from the improved temperature control of staging for maximum comfort.

– You want secondary control – In a vacation home or garage, being able to adjust cooling/heating stages from afar can be handy for bringing the space to a comfortable level before use.

– Budget isn’t a major concern – You appreciate the benefits of a more advanced thermostat and don’t mind paying a bit more for quality and features.

Conclusion

Both 1 stage and 2 stage thermostats have their benefits. The type you choose mainly depends on your HVAC system, climate, desired features and budget.

If you have a single stage heating/cooling system, mostly want simple operation and don’t require precise control, a 1 stage thermostat is a great affordable option.

For multi-stage HVAC systems, tight temperature control, and advanced features like smart scheduling and remote access, a 2 stage thermostat is worth the extra investment.

Carefully considering your needs and home setup will ensure you select the right thermostat model to maximize comfort and efficiency all year round. With this breakdown of how 1 stage vs 2 stage thermostats work and differ, you have the key information to make an informed decision for your climate control needs.

Frequently Asked Questions about 1 Stage vs. 2 Stage Thermostats

Can I use a 2 stage thermostat for a 1 stage system?

Yes, you can use a 2 stage thermostat on a single stage system. However, you won’t see any benefit in efficiency or temperature control since the system only has one stage of heating/cooling. The 2 stage thermostat will operate just like a 1 stage model on a single stage system.

Is a 2 stage thermostat worth it if I don’t have AC?

You can benefit from a 2 stage thermostat on heating-only systems for better temperature control in winter. The staging allows more incremental heat levels, rather than blasting at 100% on a 1 stage model. This improves comfort and can save energy.

Can I upgrade from 1 stage to 2 stage without replacing my whole HVAC system?

Sometimes yes, provided your heating/cooling equipment is compatible. For example, installing a variable-speed blower motor in a furnace often allows upgrading just the thermostat to 2 stage for improved control. Consulting an HVAC pro on system compatibility is recommended.

Do I need a new thermostat wire for a 2 stage installation?

Most standard 5 or 8 wire thermostat cables can support 2 stage thermostats. However, sometimes an 18-8 wire upgrade is needed for true 2 stage operation, if the heating and cooling share wires currently. An HVAC technician can advise if new wiring is required.

How much more does it cost to run a 2 stage thermostat?

When heating or cooling is needed, properly installed 2 stage thermostats can actually reduce energy costs compared to less efficient 1 stage models. Less runtime at the higher stage is more efficient. The only added cost is if you program tighter temperature swings that require more total runtime.

What temperature swing should I set on a 2 stage thermostat?

Most experts recommend a 1-1.5 degree F swing from the setpoint to activate stage 1 heating or cooling, and 3 or more degrees to trigger both stages. Wider swings save energy but reduce temperature precision. Tighter swings maintain more constant temps but increase system runtime.

Can I add zones to my 1 stage thermostat?

Basic 1 stage thermostats aren’t designed to support independent zoned climate control. However, adding a multi-zone control panel allows connecting multiple 1 stage units on different zones. This requires professional installation.

Should I get a smart (WIFI-enabled) 2 stage thermostat?

Adding WIFI control allows remote access and automation through smart features. This is most beneficial on 2 stage models, allowing you to better customize staging and scheduling. Smart thermostats also integrate with other smart home devices.

What features do high-end 2 stage thermostats offer?

Top-of-the-line models provide touchscreen interfaces, smart schedules and algorithms, remote access and control, weather data integration, moisture management, multiple staging, HVAC monitoring, and integrations with other smart devices.

Comparion Table of 1 Stage vs. 2 Stage Thermostats

Feature	1 Stage Thermostat	2 Stage Thermostat
Temperature Control	Wider swing around setpoint (eg. +/- 3°F)	More precise control (eg. +/- 1°F)
System Compatibility	Works with single stage HVAC systems	Needed for multi-stage HVAC systems
Efficiency	Less energy efficient, full runtime at one stage	More efficient with gradual staging
Setpoints	Usually one setpoint for heating and cooling	Often has two setpoints for staging
Complexity	Simple on/off operation	More advanced features and settings
Cost	More affordable, often under $50	Higher costs starting around $100
Advanced Features	Usually just basic temperature control	Added features like smart scheduling, humidity control etc.