# Manual J: Why Your Contractor Should Know It From A To Z > In order for you to get the most value and efficiency out of a new air conditioner, your HVAC contractor should be familiar with Manual J. ![sizing a new air conditioner, Boston, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2012/05/AirCon.gif)As the weather heats up, you may be considering having a new air conditioner installed before the summer really heats up. In order for you to get the most value and efficiency out of your new climate-control system, your HVAC contractor should be familiar with Manual J. ![sizing a new air conditioner, Boston, Massachusetts](https://bc.rodenhiser.com/wp-content/uploads/2012/05/AirCon.gif) This calculation tool was created by industry experts and is used to determine the specific cooling needs of individual homes. Your HVAC contractor will be able to use these calculations to select the correctly sized air conditioning equipment for your house. Here are a few ways that Manual J will benefit you: **Air quality** Breathe easier this summer. Musty, humid conditions can be traced back to an improperly sized air conditioner. Cooling equipment that is too large will not be able to properly dehumidify your home. This will lead to problems with excess moisture, which is a breeding ground for toxic mold and mildew. **Energy efficiency** Everyone is trying to conserve energy. With high utility costs, you want to make sure that your air conditioner is running as efficiently as possible. A climate control system that is too large for your home’s actual needs will waste energy without effectively cooling your house. Your contractor should understand that sizing your air conditioner with Manual J is essential to the efficiency and cost-effectiveness of your cooling system. **Maximum comfort** Comfort is of primary importance when it comes to the installation of a new air conditioner.  Having your air conditioner properly sized with Manual J calculations will, in effect, give you a cooling system that is tailored to your needs. These calculations will tell your contractor exactly how much heat and humidity needs to be removed from your home to provide optimum comfort. Selecting the right air conditioner is more complex than simply pointing and choosing. Your contractor should be well versed in the specifics of Manual J. Proper sizing will allow you to get the most from your climate control. For more expert advice on air conditioner sizing, please contact us at [Rodenhiser Plumbing, Heating & Air Conditioning](http://rodenhiser.com/call-rodenhiser/book-online.html). We proudly serve the route 495/128 area of Massachusetts. ***Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about air conditioners and* ***other HVAC topics, download our free [Home Comfort Solutions Guide](https://bc.rodenhiser.com/download-the-home-comfort-solutions-guide.html).***** *[Air conditioner image](http://www.shutterstock.com/pic-66958438/stock-photo-high-efficiency-modern-ac-heater-unit-energy-save-solution-horizontal.html?src=lb-7785082) via Shutterstock* ## 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. 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