The attic space is a neglected area in many homes and on a hot day, a poorly insulated attic can be a very hot space. So, if you want to repurpose the attic to create an extra bedroom or a hobby room, it can be a real challenge. The most reliable way to achieve and maintain a stable temperature is to install an AC system. But, it can be tricky to find the right type of AC system to meet your needs. In this brief guide, we cover the basics to help you make an informed decision.

Why Choose the Attic?

The attic is a handy storage room, but it’s an underused space that can be a valuable addition to your home. The possibilities are endless, you could create a guest room, office, library, or any other room that meets your needs. Aside from access, the major challenge that you will need to overcome is the cooling. But, in some attics that are closed-off there are other moisture and humidity issues that may encourage mold growth. The hotter attic air will transfer warmth to the lower floors in your home and this is especially true if there is insufficient ventilation and insulation. These problems can increase the cooling costs and place additional strain on your heating and cooling equipment. Finally, it’s worth noting that cooling the attic and removing excess moisture can extend the lifespan of the roof.

6 Key Factors to Consider

Because the attic is at the top of your home, it is the most vulnerable position for temperature fluctuations. The strange shape of the roof can limit the storage space along the wall and some AC systems may not fit in the space. There are six factors that you need to consider before you get an AC system. They are:

1.   The Attic Insulation Levels

The attic spaces should be fully insulated and vented before an AC system can be installed. If these two considerations are not in-place you will lose the treated air and this wastes a lot of energy. The AC system will need to work harder than it would in a regular room in your home which significantly degrades the energy efficiency.

2.   Easy Installation

Choosing an AC system that’s easy to install and that fits in the space well is important. As an example: Installing a window AC system in an attic that has smaller roof windows would be a significant challenge. It’s also worth noting that portable units will take up too much floor space in a smaller attic.

3.   Proper AC System Sizing

The AC unit must be matched carefully to the attic space to ensure that it performs efficiently. The standard unit is British Thermal Units (BTUs) and 20 BTUs are required for each square foot of regular indoor space. But, an attic space is different, because they act as a heat trap from the roof, and with direct sunlight, they get hot quickly. If you apply the formula state earlier for a 400 sq feet attic, you would require 8,000 BTUs. But, in the attic you should add extra to offset the heat trap characteristics and 10,000 BTUs would be more appropriate. At this size, the AC system will not need to work beyond its stated capacity and the cooling performance and energy efficiency will be maintainable. It’s a good idea to contact your local HVAC specialist to size the AC unit for you.

4.   Consider a Heat Pump

Another possibility to consider is a heat pump as an alternative to an AC unit. This can keep you warm and cool throughout the entire year with a single unit. This saves space and there is no need to install an AC unit and a heating system for the attic.

5.   Longevity and Durability

It’s tempting to save money with a budget friendly AC unit, but in the medium to long-term this would be a poor investment. As an example: an inexpensive portable AC unit is likely to last for 7-10 years. But, a high-quality mini-split AC unit can last 15-20 years and it would be at the upper end of that range with regular maintenance.

6.   Energy Efficiency

When you choose your attic AC unit check the Energy Efficiency Rating (EER) to get the best balance of performance and lower energy bills. Avoid any AC units that have a rating of 9 EER or less because they will not be a good investment. If you choose air conditioner equipment with an EER of 12 or higher you can enjoy significant energy efficiency savings.

4 Suitable AC Units for Your Attic

There are four suitable AC unit types for the attic because installing ductwork to use the central HVAC system can be expensive.

  1. Mini-Split AC System
  2. Window Air Conditioner
  3. Through the Wall AC System
  4. Portable AC System (not recommended)

Installing a dedicated unit will save space and the installation will be cheaper and inexpensive in comparison. There is no need to cover the unit or carry out extensive finishing to finish your attic space.

Consider a Smart AC Control System

The EER of your mini-split, window AC units, and even portable systems can be improved if you control them with a smart system. It’s possible to control many aspects of your AC units remotely in real time from a handy app on your phone. You can automate many aspects of your attic climate and there are many modes and settings to explore. When you have unparalleled control over the temperature and humidity levels you can save a significant amount of money on your energy bills.

In Conclusion

The attic AC unit needs to cool the hottest area in your entire home with temperatures of 100ºF up to 150ºF! So, it’s important to consider which type of unit that you need to meet your comfort, energy efficiency. BTUs and durability needs. Pairing your chosen system with a smart controller will improve the convenience and EER.

If you’re considering an attic AC unit, contact your local heating and cooling specialist today.