Home Addition HVAC: How to Cool a Room Addition

Adding a new room or expanding your home is an exciting project, but keeping that new space comfortable during the hot months can be a challenge. Since home additions often have different insulation and ventilation, and may not be connected to central HVAC like the rest of the house, you may have to consider alternative cooling options for your new room addition. 

We’ve already discussed the many ways to heat a home addition, so for this installment let’s turn to the cooling aspect. In this guide, we explore various ways to cool a home addition effectively and efficiently, as well as what you should consider when choosing a home addition AC.

Factors to Consider When Cooling a Home Addition

1. Room Addition Type

The purpose and design of the room addition will help narrow down your choice of cooling options. 

Check out our cooling guides for specific room types below:

• Small rooms
• Attics
• Basements
• Garage AC options and tips for maximizing the unit
• Sunroom
• Grow room

2. Room Size

The size of the new space determines the cooling capacity needed, measured in BTUs. 

Smaller rooms can be serviced by a window or room AC, but larger spaces may require higher BTU units. 

See our AC BTU Calculator to estimate the cooling capacity needed for your room addition. This innovative tool takes into account the type of room, from living rooms to kitchens.

3. Integration with Existing HVAC

If you have a central AC, you need to determine whether it can handle the additional load, as well as the feasibility and cost of extending ductwork to the new location.

If you have a multi zone mini split, check if the system can handle an additional indoor unit, as well as the wire routing to the outdoor compressor.

4. Climate and Seasonal Use

Check which climate zone you belong in to help the temperature and humidity for your region, which can impact how often you need to cool your residence as well as affect the performance of the AC.

Next, think how often the room will be used. An attic or basement may not need the same cooling as a bedroom or living room that is used year-round.

5. Venting

ACs need access to venting to expel the hot air. Some rooms such as basements may not have windows, ruling out window ACs. 

6. Budget and Installation Costs

Some AC units cost more upfront but offer long-term savings in terms of energy efficiency.

In general, mini splits are among the most efficient types of AC compared to room air conditioners.

Cooling Options for a Home Addition

Here are the different ways to cool a home addition:

1. Extend Central HVAC

If your current central AC has the capacity to cool an additional room, extending the ductwork may be a viable option. However, it requires professional assessment and installation.

Pros:

• Provides uniform cooling throughout the home.
• Controlled by your existing thermostat.

Cons:

• Can be costly if your system lacks sufficient capacity.
• Requires extensive ductwork modifications.

2. Ductless Mini-Splits

A mini-split system is one of the most efficient ways to cool a home addition without altering the existing HVAC system. Compared to central AC, it does not require ductwork, while being more efficient than other room air conditioners.

A multi-zone mini split can also handle several indoor units. This can come in handy if you already have an existing mini split with excess capacity, or you plan to expand your home further in the future.

Pros:

• Energy-efficient and quiet.
• No need for ductwork.
• Provides independent zoned cooling.

Cons:

• Higher initial cost than window units or portable ACs.
• Requires professional installation.

Featured mini split for room additions:

Friedrich FPHW243D 24000 BTU 22.5 SEER2 Floating Air Pro Series Single Zone Mini Split

This single-zone mini split is a 208/230 volt, cooling with heat pump system. It features high efficiency ratings including a 22.5 SEER2 and 12.25 EER2.

It not only meets the standard, rigid criteria needed to receive an Energy Star Rating, it also meets the more specific, stricter standards for heating capacity and qualifies as Cold Climate Energy Star Rated. The built-in low ambient cooling capabilities will cool your space when outside temperatures are as low as 5°F. If you need to cool a server room or other equipment year round, this unit’s low ambient cooling features make it a great choice.

It is Smart Home Ready with built-in WiFi and access to Friedrich ComfortPro App for wireless control as well as Google Assistant and Alexa voice commands. The Floating Air Pro Series also uses the new refrigerant R454B, making it compliant with EPA’s new standards for refrigerants.

3. Window Air Conditioner

A window AC unit is a budget-friendly cooling option if your addition has a suitable window for installation.

Pros:

• Affordable and easy to install.
• Cools small to medium-sized rooms effectively.

Cons:

• Blocks the window and can be unattractive.
• Less efficient than other options, with limited capacity
• Emits the most noise.

Featured window unit for room additions:

Friedrich CCV12A10A 12000 BTU Chill Premier Inverter Smart Window Air Conditioner

The new Chill Premier Inverter Series is Friedrich’s Premium Line of “smart” room air conditioners now with variable comfort / inverter technology. This Energy Star Rated unit features 12,000 BTUs, and a CEER of 15.0. It uses the newer, efficient R-32 refrigerant. R32 is up to 12% more efficient than R410A, resulting in lower Global Warming Potential (GWP).

It includes Friedrich’s QuietMaster technology which provides the user with Library Quiet Operation. This is accomplished through heavy duty insulation on the inner wall for sound absorption, as well as a stiffened sheet metal casing to help block external noise. Vibration reducing counterweights also help to reduce the sound. Additionally, the wide discharge vents optimize airflow and minimize front panel noise.

4. Portable Air Conditioner

If a window AC isn’t an option, a portable air conditioner offers flexibility. They also come in vented and ventless options.

Pros:

• Easy to set up
• Can be moved as needed
• No permanent installation required.

Cons:

• Requires a venting solution for hot air exhaust.
• Typically less efficient than mini-split or window AC units.

Featured portable AC for room additions:

Friedrich ZHP14DC 14000 BTU Class ZoneAire Dual Hose Portable Air Conditioner Plus Heat Pump with Built-In WiFi

This 4-in-1 portable air conditioner gives you all the power and functionality of a Friedrich Window unit in a portable package, plus dehumidification and fan, PLUS a Heat Pump. It offers 14,000 BTUs of cooling, enough for a room that is about 700 sq. ft.

It also has a 9,000 BTU heat pump and three modes (air, fan and dehumidifier). The dehumidifier function can remove 3.4 pints of moisture per hour (81 pints per day).

The unit boasts built-in WiFi for on the go control through the ConnectPro app. It also supports voice commands with Amazon Alexis and Google Home. 

5. Through-the-Wall Air Conditioner

Similar to a window AC, a through-the-wall unit is a more permanent cooling solution, without requiring a window for installation.

Pros:

• Saves window space
• More efficient than window ACs
• Aesthetically pleasing compared to window units.

Cons:

• Requires cutting a hole in the wall, which can be costly and permanent.
• May require professional installation.

Featured through-the-wall AC for room additions:

GE AZVS15DCXWA 15000 BTU Class Zoneline PTAC Air Conditioner with Heat Pump

This 14,200 BTU PTAC comes with a variable heat pump that delivers between 4,000 – 14,000 BTUs of heat. It is a fixed speed unit with hi or low settings and includes Corrosion Protection.

GE Zoneline heat pump PTACs are more efficient than most other leading competitors in their class, cutting any building or establishment’s monthly energy costs significantly. The heat pump on the inverter, variable speed PTAC unit will operate down to 0°F and also has a heat boost option.

The electric heat is power cord dependent. 15, 20 and 30 Amp cords are available for this unit. At Total Home Supply, we include your choice of power cord with your purchase.

6. Evaporative Coolers

If you live in a dry climate, an evaporative cooler or swamp cooler can be an efficient and eco-friendly solution.

Pros:

• Uses less energy than traditional AC units.
• Adds moisture to dry indoor air.

Cons:

• Not effective in humid climates.
• Requires regular maintenance and water refilling.

7. Ceiling Fans and Ventilation

For mild climates or as a supplement to another cooling system, ceiling fans and ventilation can also help cool a new room.

Pros:

• Cheaper than AC units
• Less utility cost

Cons:

• Doesn’t actively lower the room temperature.
• Less effective in hot climates.

Keep It Chill in Your New Space

Cooling a home addition requires careful planning to ensure efficiency and comfort. While extending an existing HVAC system may work in some cases, alternatives like mini-split air conditioners, window units, or portable ACs can provide better performance depending on the room type, size and other factors. 
We carry all types of AC cooling solutions that’s sure to fit your new space. If you find yourself a bit over your head, drop us a line and we’ll help you chill out and enjoy your new addition, without the headache.