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If you're looking for an independent source for load calculations and HVAC design guidance for high performance homes, you've come to the right place!  If you haven't already done so, be sure to check out these two "must read" guides (linked in right-hand margin):

  7 Reasons Why Oversizing is a Bad Idea

  10 Reasons Why Oversizing Persists

Online Interactive Project Submittal (Project Manager / registration / log-in is currently disabled)

In order to do business with Optimal Building Systems, you'll need to register so you can access our online Project Manager, an interactive form that allows you to create and submit load calc projects. This powerful tool guides you along as you enter the data we need to model a home – like insulation and window details that are not usually provided on constructions drawings. The online help files are a veritable mini-course in building science.

Project Manager is designed to be fast and efficient. It only takes about 15 minutes to set up a project from start to finish if you have all the information at hand. If not, you can save your partially completed project file and return later to enter the remaining information. One feature you'll appreciate is the ability to use one of your previous projects as a template for subsequent projects. Just update the information that's different and you're done!

Once we receive your project submittal, we'll review the data along with the construction drawings. If everything is in order, we'll send you a quote along with the estimated time-to-completion. Actual turnaround depends on our work backlog at the time we receive your deposit.

Retail Prices

Each new construction load calc project is individually priced based on the following schedule. Our pricing policies are designed to keep costs as low as possible for the majority of homes. Additional services are available on an hourly basis. You can download our retail price sheet here.

Load calculations (new construction) 1

• $140 plus 8¢ per square foot conditioned area ($299 minimum)

• $60 for each additional HVAC system (first system included in base price)

• $45 and up for special architectural or design features such as basements, multiple vaulted or volume ceilings, attic knee-walls, and/or unconventional wall systems

• Load calculations based on ACCA Manual J, 8th Edition

Optimized mechanical systems specifications

• $175 flat rate for homes with single HVAC system

• $75 for zoned systems or per additional HVAC system

• Equipment selection based on ACCA Manual S

• Equipment sizing and match-up based on expanded engineering data from manufacturer

• Equipment specifications optimized for each project based on local climate and utility costs

• Specifications include duct system guidelines
Note: We do not offer duct system design services (see FAQ regarding Manual D).

Repeat pricing and professional discounts

• $75 for repeats with new orientation and/or mirror plan - assumes no other changes

• Repeats with changes - hourly fee applies ($75 minimum)

• Revisions to a previously completed load report - hourly fee applies ($75 minimum)

• Volume discounts available to raters & auditors – contact Optimal Building Systems for details

Completed energy rating file (Certified Raters only)

• Provide Rem/Rate building (.blg) file – contact Optimal Building Systems for pricing

Hourly services ($120/hour)

• optimization of insulation and glazing specifications

• evaluate load calculations performed by others

• solar (PV) system sizing; evaluate cost performance vs. potential efficiency improvements

• HVAC design for home theaters

• HVAC and envelope design for off-grid homes

• HVAC and envelope design for indoor swimming pools (natatoriums)

Payment terms

• 50% deposit required on all work with balance due at completion

• Major credit cards, PayPal, and checks accepted

1 Load calculation prices apply to new construction. Homes must participate in Energy Star or other 3rd-party verification program that includes thermal bypass & insulation inspections, blower door and duct leakage tests. We can arrange for these site verifications upon request. Note: Projects involving existing homes are accepted on a case-by-case basis. Contact Optimal Building Systems for pricing and acceptance criteria.

The Elephant in the Room - HVAC for High Performance Homes
7 Reasons Why Oversizing is Bad
10 Reasons Why Oversizing Persists
Furnaces in High Perf. Homes
ACCA HVAC QI Checklist
The Case Against HRV Systems
The Case Against Partially Conditioned Basements
Point-of-Use Alternatives to Hot Water Circulation Systems
Tankless Water Heaters
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