Custom HVAC projects require a larger investment for the following reasons: Custom HVAC projects usually have more equipment integrations like zoning systems, humidifiers, advanced IAQ products, linear diffusers, etc. Crew labor days – Custom HVAC installations require a dedicated project manager and have significantly more ‘crew labor days’ allocated to them in order to complete the projects. Call us at (714) 332 – 6302 for more information.