Software allows input of data from instrument readings and gives solution to the problem. Definition and help section provides additional information about concepts and functions. Demonstration version available.

Interactive manual includes basic troubleshooting and maintenance tips for do-it-yourselfers. Feedback form provided for technical questions.

Diagnostics chart for troubleshooting. Tips on air filters, refrigerant charging, thermostats, and operation.

Input a desired flow rate in CFM, a limiting velocity in FPM, air temperature in degrees F, the length of the duct, and the duct material. The program calculates the duct cross sectional area, the circular duct diameter, and rectangular duct equivalents.

Volunteer mechanics answer questions via e-mail. Volunteers can be evaluated based on credentials and user ratings.

List of do's and don'ts for maintenance and repair.

For humidifiers, air cleaners, thermostats, zone control systems and fresh air exchangers.

Factsheets on purchasing a new system, determining proper size, ductwork, grilles, and a glossary of industry terms.

Mechanic answers homeowner's queries on a wide range of service concerns.

Tutorial illustrating step by step procedures for finding refrigerant leaks.

Tutorial illustrating step by step procedures.

Estimate the heating needs of a room, combination of rooms, or an entire home.

Legal, environmental and technical information.

Comprehensive site includes safe/unsafe practices, effects, detector placement, and discussion.

EPA site provides advice on CO detectors, poisoning symptoms and prevention.

Guidelines to determine whether potential exists for this deadly gas to enter a house.

EPA tips on how to determine if ductwork needs cleaning. Criteria for choosing a contractor.

Short example on replacing bearings and fan belt.

Warning about the potential danger if flue pipe is not replaced when a modern high efficiency furnace is installed. (click "alert" to get to page)

Everything from troubleshooting to maintenance and repair.

Information on gas, wood, pellet, and coal appliances. Cost comparison of the different fuels.

Fact sheet illustrates the theory and operation. Add-on device for air conditioner to improve de-humidification.

Tips on preparing a furnace for winter operation.

Find answers to steam heating problems by posting questions for experts or reading excerpts from books about heating.

Order form to request free literature on new units and related products.

Wide assortment of tips including programmable thermostats, cleaning air ducts, reducing moisture problems, and basic maintenance.

Devices include thermostats, humidistats, air cleaners and humidifiers. Everything from manuals to troubleshooting guides to programming instructions to product support.

Article that describes air conditioning operation from window units up to large industrial applications.

Consumer guide to the array of efficiency ratings, abbreviations and acronyms used to describe or explain the products.

Experienced mechanic shows how to get help from the web. Includes advice from other mechanics and numerous searches of alt.hvac where many industry experts have answered a variety of questions.

Information and support on heating, ventilation and air conditioning systems or controls for home owners and professionals. Knowledge base, recalls, forum, glossary, and events.

Advice geared toward historic or older homes.

Software bulletin board for HVAC contractors, home-owners, do-it-yourself enthusiasts to use for heating and air conditioning concerns.

Advice from a service manager on buying a new unit, illustrated essay on chimney liners, and a history of brand names.

Illustrated tutorial on fabricating sheet metal ductwork.

Overview of systems which contribute to climate within the home - insulation, air conditioners, vents, humidifiers and dehumidifiers, forced air heaters, filters, and thermostats. Illustrations, common problems, and basic repair instructions.

Technical support and regulatory updates; articles, faq, and news.

Homeowner checklist for oil furnace malfunction.

Liquid propane gas serviceman's handbook. Installation and inspection instructions.

Illustrations and detailed tutorials for installation of radiant floor heating.

How to locate, repair, and seal ductwork.

Searchable database provided by Consumer Product Safety Commission.

Flat rate price guide for checking repair costs.

In-depth articles on topics related to improvement, care, and maintenance.

Instructions on maintenance procedures for heating systems. Includes drawings and diagrams.

Forum to post residential steam related questions.

Information on heating system operation, components, troubleshooting and maintenance.