Updated: Dec 19, 2022.
Looking for a more efficient, faster way to cool your home? A ductless mini-split system could be exactly what you need. However, before you decide to invest, you'll need to know a few things, including how to size the system correctly.
What Are Ductless Mini-Split Systems?
First, let's address what we mean by ductless mini-split systems and how these differ from central heating and cooling systems. Like central HVAC systems, ductless mini-split systems can heat and cool your home.
However, unlike those systems, these do not require any ductwork connecting the rooms in your home. Instead of one large system connected by ducts, you'll have a network of smaller ductless mini-split units, each designed to cool the space in which it's installed.
Why Consider a Mini-Split System?
Why go this route rather than a more conventional central HVAC system? You'll find several reasons, including the following:
- Improved energy efficiency
- The ability to create a "zone" heating/cooling strategy
- Improved heating and cooling of your most-used spaces
- Improved flexibility in home design and space utilization
Explore these mini-split heat pump benefits and more.
Why Is Sizing A Ductless Mini Split Important?
While a ductless mini-split system is more efficient than other heating and cooling options on the market today, size is a critical consideration. If the system is too small, it will waste energy trying to continuously heat or cool your space. If the system is too large, it will suffer from short cycling and will fail prematurely.
Given how important sizing is, how do you make sure that you get the right-sized system for your needs?
First, get used to the different terminology. Most central air systems are measured in tons – the amount of heat that a unit can remove from your space in one hour. However, ductless mini-split systems are measured in BTUs, or British thermal units, because they don't heat or cool the entire home, just one part of it.
How To Size A Mini Split System
The first thing you'll need to do is figure out how to size a mini split system. You will need to measure the space to be heated or cooled. Measure each room where you intend to install a mini-split unit so you can get the right size. To get the square footage, measure the room's length and width and then multiply them together. So, a room that is 15' x 15' would be 225 square feet. With that measurement, you can start considering your options for units based on their BTU rating. Here's a quick breakdown to follow:
Up to 250 square feet: 6,000 BTUs
250 – 300 square feet: 7,000 BTUs
300 – 350 square feet: 8,000 BTUs
350 – 400 square feet: 9,000 BTUs
400 – 450 square feet: 10,000 BTUs
450 – 550 square feet: 12,000 BTUs
550 – 700 square feet: 14,000 BTUs
700 – 1,000 square feet: 18,000 BTUs
1,000 – 1,200 square feet: 21,000 BTUs
1,200 to 1,400 square feet: 23,000 BTUs
What size mini split should I use for a bedroom?
Depending on the size of your bedroom, we recommend using a 6000 BTU to 800 BTU mini split. For example, a 10x10' foot room is only 100sq/ft, and you will easily cover this room and others on the same floor with a 6000BTU unit.
A great consideration with bedrooms close together is using a single mini split to accommodate multiple rooms or an entire floor. The team at Home Mechanics can help identify placement of your mini split for the best airflow and coverage.
What size mini split should I use for an attic?
Attics are trickier and may require the assistant of an HVAC professional with experience in installing mini splits or ductless A/C units. A few considerations: the area covered, the condition of your roof and insulation, and installation access points. If your attic has a low ceiling, it may be trickier to install the properly size unit.
Typically most attic users install a 6000 to 8000 BTUs unit depending on the size of their attic.
How much does it cost to install an AC mini-split?
On average, typical Massachusetts home owners spend between $8,000 to $35,000.
The cost to install a ductless A/C mini split unit can vary depending on how many units, and how many zones are needed to properly heat and cool your home.
Other factors that impact your mini-split system
In addition to square footage, you also need to consider other factors. A few examples include:
Inadequate insulation. If you have inadequate insulation you will need more power to heat or cool the living space to your preferred temperature.
Climate. Like insulation, your relative climate also impacts how hard the ductless units will work to acquire the ideal temperature.
Interior and exterior mounting locations
In some scenarios, interior and exterior mounting locations can mean more complex installs or being mounted improperly if not planned for. It is imperative you invite HVAC professionals to assess the optimal installation locations to ensure you live in comfort.
With the right-sized ductless mini-split system, you can enjoy efficient heating and cooling. You can also benefit from a zoned climate control strategy that improves your comfort while reducing your energy usage and your demand for natural resources.
Are you looking to work with an experienced team of HVAC Technicians ? Call Home Mechanics for your heating, cooling, plumbing, and electrical needs or email us directly at info@homemechanics.com. We are always ready to provide you with the best HVAC solutions.
Feel free to reach out. We’d be happy to help!