Rhvac makes HVAC load calculations, duct sizing, equipment selection, and sales proposals as easy as they can be - with one-click help on virtually every input, favorite material lists, automatic error checking and more. No HVAC design program does more than Rhvac for just $495. Try it and see if it isn't the most user-friendly and powerful HVAC design program on the market today.

Features

• Calculates peak heating and cooling loads in accordance with ACCA Manual J Eighth Edition, Version 2.
• Calculates Duct Sizes, System Losses, and fan static pressure requirement in accordance with ACCA Manual D. Lets you enter the entire duct system, or only the path(s) with the highest pressure loss if you prefer.
• Determines building tonnage and room CFM requirements.
• Helps Comply with ACCA Manual S Equipment Selection Requirements.
• Helps Comply with the International Residential Code (IRC) and the International Energy Conservation Code (IECC).
• Incorporates Manual J Addenda A, B, C, and D!
• Links to REM/Rate, Architectural Energy Corporation's popular home energy rating tool.
• Links to REScheck, DOE's energy codes program.
• Links to the Energy Gauge USA home energy rating program.
• Generates a Building Rotation report that shows you tonnages and room CFM requirements at each rotation.
• Includes a Buiding Rotation Duct Size Preview window that shows you the heating and cooling CFM for each room or duct in the project for each rotation of the building, as well as the maximum duct size of all rotations.
• Calculates hydronic radiant floor tubing length required.
• Follows ACCA Manual J, 8th Edition. Rhvac is approved by ACCA.
• Computes room by room, zone, system & building.
• Calculates from manually entered data or directly from floor plans created with Drawing Board (sold separately).
• Rooms and zones can be assigned to 15 systems.
• Allows 1000 rooms grouped into 10 zones per system using drag and drop zoning techniques.
• Allows 20 walls, 20 windows, 8 roofs, 6 floors and 6 doors per room.
• Includes a wide selection of spray foam and SIP roofs and walls.
• Allows custom construction materials and descriptions.
• Lets you specify lists of "Favorite" materials so you can select them easier.
• Remembers your most recent material selections so you can reselect them easily.
• Looks up HTM & U-values or lets you specify them.
• Determines Adequate Exposure Diversity status.
• Links to Manual D Ductsize, Bill of Materials, Energy Audit, ECA Ground Loop Sizer, PsyChart and HVAC Solution. The PsyChart program can import Rhvac system data directly into its Air Handler Model window.
• No copy protection!
• Displays psychrometric chart.
• Lets you select equipment from ARI and GAMA databases.
• Prints exploded color pie charts, bar graphs, and custom sales proposals.
• Allows decimal feet, feet-inches or metric length and width dimensions.
• Allows exterior shading (overhangs and offsets).
• Provides inputs for summer & winter partition temperature differences.

Overview

Rhvac quickly and accurately calculates peak heating and cooling loads for residential and small commercial buildings in accordance with the eighth edition of the ACCA Manual J. The Heat Transfer Multipliers (HTM values) for all the walls, windows, doors, and roofs listed in Manual J are stored and automatically looked up by the program as needed. Although HTM values are taken from Manual J directly, the user does have the option of entering his own U-Value for each wall, roof, or glass section so that a modified HTM value is used. Design weather data for over 1500 cities is built-in to the program. In addition, the user can revise the existing weather data and add additional weather data as desired. Zoning cfm adjustments are automatically handled by the program as needed. Other outstanding features include exterior glass shading, ventilation air, miscellaneous latent loads, default room data, automatic rotation of the entire building, hydronic heat calculations and much more.

Besides calculating peak heating and cooling loads, Rhvac can also calculate the length of tubing needed for hydronic radiant floors. It also calculates your duct sizes in accordance with Manual D, as well as the static pressure loss of your duct system, showing you the static pressure requirement of your system fan. Duct sizing options include all types of duct materials, height and width restrictions, velocity limits, and more. Additionally, Rhvac creates sales proposals and selects HVAC equipment. For equipment selection, Rhvac is provided with a database derived from ARI and GAMA of thousands of equipment models from over 250 HVAC manufacturers. Standard air conditioners, heat pumps, furnaces, boilers, and ground source heat pumps are among the types of equipment Rhvac can select. The sales proposal feature of Rhvac prints key features of the proposed equipment and work to be performed. Also included are standard terms and conditions of the proposal. Rhvac shares data with Elite Software's Energy Audit operating cost analysis program, Ductsize, Quick Quote, and Drawing Board program. Rhvac can be used stand alone or in conjunction with any of these programs.

Calculation Method

Rhvac's calculations are performed per ACCA Manual J 8th Edition, Version 2, and ACCA Manual D. Rhvac is an ACCA approved Manual J and Manual D computer program. Elite Software is a technical software partner with ACCA.

Powered By ACCA Manual J

The recently released 8th edition of Manual J is a significant expansion over the 7th edition. There are numerous changes, but the most noticeable is a much larger list of built-in floor, roof, wall, glass and door materials. The 7th edition was missing references to current popular materials such as structurally insulated panels, insulated concrete forms, logs, and much more. The 8th edition includes all these materials plus all common building materials with hundreds of variations. This writer's opinion is that the roof, wall, and glass loads tend to calculate slightly lower in MJ8 compared to calculations made with MJ7 and attempting to equalize all other factors.

Duct gains and losses are another area much changed in the 8th edition. Many more scenarios of duct system type, duct location, insulation values, temperatures, etc. are considered in the 8th edition. Generally speaking, duct gains and losses calculated using MJ8 procedures will be larger than what was calculated using MJ7 procedures.

MJ8 also introduced several new concepts including adequate exposure diversity (AED) , average load procedure plus excursion method, and the peak fenestration gain method. If an area of a building served by a single HVAC system is deemed to not have AED, that entire area is considered to have an "excursion," which means that an additional sensible gain load is automatically added at the system level.

In summary, the new MJ8 HVAC calculation procedures are the state of the art in HVAC design. The MJ8 procedures provide higher accuracy than the MJ7 procedures, and perhaps even more importantly, they provide far greater flexibility in analyzing modern building construction materials and techniques.

Powered by ACCA Manual D (Ductwork Design)

Rhvac can help you in several ways on sizing ductwork. For those who do not want to enter complete details about a duct system, Rhvac can still suggest the number of registers needed for each room, the runout duct size leading to each register, and the initial size of the main trunk duct. For example, if a family room is calculated to require 200 CFM, Rhvac will suggest two registers to deliver 100 CFM each. And if flex duct was specified, Rhvac will "spin the ductulator" for you and calculate using the equal friction method that each duct should be 6" in diameter. And if the project needed 1200 CFM total, Rhvac knows that the first part of the main trunk has to carry that much air and it will calculate the main trunk size. Automatically, for every project, Rhvac will tell you runout duct sizes and the initial main trunk size. All you have to do is say what materials (steel, ductboard, or flex duct) are being used for trunk and runout ducts. You get lots of duct info with minimal input required.

If you want to do a complete Manual D duct system analysis and include every duct section and fitting in the project, Rhvac also provides a free Manual D Duct Sizer. This is a tabular input procedure as shown here where you can either enter your entire duct system or just enough to calculate the fan static pressure requirement using a single route or "path." This unique tool includes a powerful Fitting Selector dialog that makes it easy to select from hundreds of fittings from ACCA's Manual D. For those who want to do a graphic Manual D analysis consider adding the Drawing Board and graphic Manual D Ductsize options to Rhvac.

Drawing Board and Graphic Manual D Duct Sizing

The basic version of Rhvac provides complete Manual J load calculations and Manual D duct sizing using a simple manual entry tabular input process. The basic version of Rhvac provides no drawing capability, except at a demonstration level.

To be able to draw floor plans and have duct sections automatically placed and sized on the drawing, you need to activate both Drawing Board and the graphic Manual D Ductsize modules in Rhvac. These modules are already inside of basic Rhvac, but operating at a demo level that limits the size of the building and number of duct sections that can be drawn.

Once these modules are activated, you can draw and calculate any size floor plan desired with any number of duct sections required. See the sample drawing here.