Ductless split system heat pumps, also known as mini-splits have become more prevalent in residential construction in the past few years, particularly for small home additions. There are some advantages to using these systems over ducted a/c systems, but of course its not all rosy – there are some disadvantages. To determine whether or not it’s the right choice for your project, here’s a look at the facts about mini splits:
Advantages:
- They’re easier to install because there’s no ductwork. This should translate into lower labor costs comparatively.
- Flexibility: you can place the fan coil anywhere in the room addition or renovation. You don’t have to worry about providing enough attic space for ductwork with a mini split, and you don’t have to worry as much about interferences with the new mini split system with existing attic components, like plumbing or electrical.
- They typically have higher efficiencies than ducted a/c systems. Because mini-splits have no ductwork, they can greatly reduce the heat and energy loss common with ducted systems. For an addition like a Florida room, the higher mini split efficiency is a must have on the energy compliance forms, in order to offset higher solar effects due to large percentages of wall glass, and produce a passing score.
- For an addition using a mini-split, the plan review and inspection process will be a little easier compared to a ducted a/c system. With the mini-split, there’s no Manual D ductwork design requiring municipal plan review, nor a duct leakage test needed in order to pass inspection.
- You can sometimes run the smaller mini split heat pump units off of a 120V circuit. Usually you do not have this option with ducted split system heat pumps and have to use a 240v circuit.
Disadvantages:
- Higher initial cost – be prepared to pay 10-20% more for the mini-split vice the ducted split system heat pump. Thus, whatever you might have saved on ductwork labor cost, you likely to need to spend for the additional mini split heat pump equipment.
- Air supply is limited to one (or sometimes two) fan coil units. So one mini-split system will not work effectively for multi room additions and multi room renovations.
Use the above advantages and disadvantages before deciding whether a mini split heat pump is the right choice for your project. Consult with the owner too – there is an aesthetic factor with mini split fan coils which may or may not be appealing to the owner.