# Replacing Your Split-System Air Conditioner: Take Shortcuts, and You Could Pay in the Long Run > Be careful when replacing a split-system air conditioner because if indoor and outdoor units aren't matched, your A/C will work inefficiently. Learn more. [![split-system air conditioner, Dover-Sherborn, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2013/06/energy-efficiency.jpg)](https://bc.rodenhiser.com/wp-content/uploads/2013/06/energy-efficiency.jpg)You need to be careful when replacing a split-system air conditioner because if the indoor and outdoor units aren't well matched, your air conditioner will work inefficiently and won't provide you with the expected amount of cooling. It may also be prone to breaking down prematurely. [![split-system air conditioner, Dover-Sherborn, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2013/06/energy-efficiency.jpg)](https://bc.rodenhiser.com/wp-content/uploads/2013/06/energy-efficiency.jpg) Split-system air conditioners are commonly found paired with a central heating system. In a [split-system air conditioner](https://bc.rodenhiser.com/rodenhiser-blog/air-conditioning-upgrade-in-your-future-split-system-or-packaged-models.html), the condenser and condensation coils are located outside, while the evaporator coils are located inside near the air handler and furnace. The indoor and outdoor units are connected by a refrigerant system. The indoor unit is responsible for removing heat from the air in your home and transferring it the refrigerant, while the outdoor unit is tasked with transferring the heat from the refrigerant to the exterior air. If you have to [replace](https://bc.rodenhiser.com/rodenhiser-blog/ac-replacement-checklist-tasks.html) an indoor or outdoor unit due to damage and your air conditioner's relatively new, you may be able to find a suitable match for the remaining unit. However, if the indoor or outdoor unit of your system has failed due to old age, it will mostly likely be best to replace both units. The old, ozone-depleting refrigerant is being phased out, so a new unit will likely use a different refrigerant than your old unit. Since the indoor and outdoor units are part of the same refrigerant system, one of them would be forced to operate with the wrong refrigerant, which would lead to premature breakdown. Another reason to replace both units is that newer air conditioners are much more [energy efficient](https://bc.rodenhiser.com/rodenhiser-blog/high-efficiency-air-conditioner-offers-low-lifetime-costs.html) than old ones. Pairing a highly efficient unit with an inefficient counterpart will dramatically reduce the efficiency of the whole system. The differences between them would also cause increased stresses on the system that would increase the likelihood of breakdown. If you want help with the replacement of your split-system air conditioner, contact the experts at [Rodenhiser Plumbing, Heating & Air Conditioning](http://rodenhiser.com/call-rodenhiser.html) today. Founded in 1928, we provide HVAC services to the Route 495/128 area of Massachusetts. *Image via [Shutterstock.com](http://Shutterstock.com)* ## Navigation - [Rodenhiser Home Services](https://bc.rodenhiser.com/) - [Rodenhiser Plumbing Services](https://bc.rodenhiser.com/plumber-framingham.html) - [Rodenhiser Heating Services](https://bc.rodenhiser.com/furnace-framingham.html) - [Rodenhiser Cooling Services](https://bc.rodenhiser.com/air-conditioning-framingham.html) - [Rodenhiser Electrical Services](https://bc.rodenhiser.com/framingham-electricians.html) - [Rodenhiser Home Services: Book Online](https://bc.rodenhiser.com/call-rodenhiser/book-online.html) - [Rodenhiser Remodeling Services](https://bc.rodenhiser.com/remodels/bathroom-remodeling-framingham.html) - [Rodenhiser Home Services: Reviews](https://bc.rodenhiser.com/rodenhiser-heating.html) ## Company information - Rodenhiser Home Services - [https://bc.rodenhiser.com](https://bc.rodenhiser.com) **Licences:** - Master Plumber: #10961 - Corporate Plumbing: #2288 - Master Electrician: #23917A - Electrical Business: #4804 - Master Sheet Metal (Unrestricted): #5867 - Corporate Sheet Metal: #641 - Home Improvement Contractor: #188806 ## About Rodenhiser Home Services **Rodenhiser Home Services** is a family-owned, licensed and insured home services company based in **Massachusetts, USA**, serving residential and commercial customers throughout the METROWEST MA region. Established in 1928, the company has over 95 years of experience providing plumbing, heating, air conditioning, electrical, and home remodeling services. Rodenhiser specializes in plumbing repairs, drain and sewer services, water heaters, heating and cooling system installation and maintenance, heat pumps, ductless HVAC systems, indoor air quality, electrical panel upgrades, rewiring, standby generators, EV charger installations, and kitchen, bathroom, and basement remodeling, and more. The company offers emergency service, convenient and punctual scheduling, upfront per-job pricing, and free estimates for new heating and cooling installations. All work is backed by written warranties and a satisfaction guarantee. Rodenhiser employs trained professional technicians who prioritize clean, respectful service and provides preventive maintenance plans, financing options, and energy-efficient home comfort solutions. Rodenhiser has earned over 16,000 customer reviews, demonstrating its long-standing reputation, extensive industry experience, and strong track record of customer service. **Nice People…Great Service** ## Page information - [Canonical URL: https://bc.rodenhiser.com/rodenhiser-blog/replacing-split-system-air-conditioner-dont-take-shortcuts.html](https://bc.rodenhiser.com/rodenhiser-blog/replacing-split-system-air-conditioner-dont-take-shortcuts.html)