WHAT IS DRAIN WATER HEAT RECOVERY?
How does residential drain water heat recovery work? What can it do for you?
North America's Leading Passive DWHR Technology
Residential Drain Water Heat Recovery (DWHR)
Every time someone in your home showers, hundreds of kilowatt-hours of expensive thermal energy wash straight down the sewer. The ThermoDrain® TDX Series captures that heat instantly and silently—preheating incoming cold groundwater before it reaches your water heater. The result is up to 3x more hot water shower delivery, a 30% to 40% reduction in water heating utility costs, and the fastest payback of any residential clean-energy investment.
+100,000
ThermoDrains Installed
Up to 40%
Water Heating Energy Cut
100% Vented
Double-Wall Drinking Safety
0 Moving Parts
Zero Maintenance / 40+ Yr Life
Explore Residential DWHR by Sector
Find the exact specs, financial incentives, and guides for your specific role:
🏡 For Homeowners →
Learn how ThermoDrain ends morning shower arguments, triples hot water capacity, and pays for itself within 2 years.
🔧 For Plumbers & Trades →Direct glue-in drain connections, factory PEX fittings, 45-minute install times, and wholesale contractor pricing.
🍁 Canadian Energy Hub →HOT2000 modeling parameters, BC Step Code, OBC SB-12, Novoclimat, and 25% CMHC Eco Plus mortgage refunds.
🇺🇸 US 45L & HERS Hub →Ekotrope / REM/Rate inputs to drop HERS scores by 1–3 points and qualify for $2,500–$5,000 Section 45L tax credits.
Best Value Spotlight
TDX3240: The Highest ROI in Clean Energy Technology
Starts at ~$185 USD
(~$250 CAD Equipment Only)
Evaluating energy technology comes down to cost per percentage of energy recovered. While heat pump upgrades or solar arrays require thousands of dollars in capital with 10- to 15-year paybacks, the compact ThermoDrain TDX3240 (24" length) delivers 33.59% certified heat recovery at just ~$5.50 USD per 1% of efficiency. It pays for itself in 1.5 to 2.5 years, then continues delivering free energy for the lifetime of the plumbing stack.
Cost Per % Efficiency
~$5.50 USD / 1%
Lowest capital cost per energy unit recovered in residential building science.
Rapid Payback Window
1.5 to 2.5 Years
Outperforms heat pumps, windows, and solar arrays in time-to-breakeven.
Compact 24-Inch Design
Fits Low-Clearance Stacks
Perfect for tight basements, split-levels, crawlspaces, or utility rooms.
How It Works: Clean, Passive Physics in Plain English
Zero motors, zero electronic sensors, zero electrical connections. 100% natural thermal physics.
Falling Film Dynamics
1. Water Hugs the Pipe
When warm shower water (~100°F / 38°C) drains down a vertical stack, natural surface tension forces the water outward against the pipe walls. Rather than dropping freely in the center, it clings to the copper wall in a paper-thin, falling film.
Copper Conduction
2. Heat Moves Outward
Copper conducts heat up to 20 times faster than stainless steel or plastic. As fresh, cold municipal water circulates through tightly wound copper coils wrapped around the outside of the drain pipe, it instantly pulls the heat through the copper wall.
Preheated Intake
3. Pre-Warmed Supply
Incoming cold water is boosted from 45°F–50°F (7°C–10°C) up to 70°F–80°F (21°C–27°C) before reaching the water heater and the shower valve. Your water heater works less, delivering virtually continuous hot water.
Dual-Metal Engineering: Stainless Steel Shell + Copper Core
ThermoDrain TDX units feature an outer stainless steel armor jacket protecting an interior antimicrobial copper heat transfer core. The stainless shell guards against jobsite handling damage and moisture, while the copper core ensures maximum conductive efficiency.
🛡️
100% Drinking Water Safety: True Double-Wall Vented Protection
Can greywater ever contaminate clean tap water? An absolute, physical NO.Every ThermoDrain is engineered with patented True Double-Wall Vented Technology certified under North America's strictest plumbing safety codes (CSA B55.1 / CSA B55.2 / IAPMO IGC 346):
Two Distinct Metal Walls
The drain pipe and the potable water coil have completely separate metal walls. They do not share a single surface.
Continuous Open-Air Vent Gap
If either wall were ever breached over a century of use, water would safely vent externally to the floor rather than enter your drinking water.
Universal Plumbing Approvals
Full municipal approval across Canada (National Plumbing Code) and the United States (Uniform Plumbing Code / International Plumbing Code).
Residential TDX Model Sizing & Performance Specifications
All TDX models feature direct solvent-weld (glue-in) drain hubs and factory-installed 3/4" PEX fittings.
| Model Series |
TDX Compact (24") TDX3240 (Best Value / Fastest Payback) |
TDX Builder Pro (35") TDX3350 (Code Standard / SB-12) |
TDX Net-Zero Pro (61.5") TDX3615 (High-Yield / Step 5) |
|---|---|---|---|
| Approx. Equipment Cost | ~$185 USD / $250 CAD | ~$325 USD / $425 CAD | ~$525 USD / $695 CAD |
| Certified Heat Recovery (CSA B55.1) | 33.59% | 42.10% | 55.04% |
| Cost Per 1% Heat Recovery | ~$5.50 USD (Lowest) | ~$7.70 USD | ~$9.50 USD |
| Estimated Payback Period | 1.5 to 2.5 Years | 2.5 to 3.5 Years | 3.5 to 5.0 Years |
| Stack Height (Cutout) | 24.0 inches (61 cm) | 35.0 inches (89 cm) | 61.5 inches (156 cm) |
| Drain Connection Type | Direct Solvent Weld (Glue) | Direct Solvent Weld (Glue) | Direct Solvent Weld (Glue) |
| Potable Water Fittings | 3/4" PEX (F1807 / F1960) | 3/4" PEX (F1807 / F1960) | 3/4" PEX (F1807 / F1960) |
| Pressure Drop @ 2.5 GPM | < 1.8 psi (Imperceptible) | < 2.5 psi (Imperceptible) | < 3.2 psi (Imperceptible) |
| Recommended Use | Low-clearance basements, quick paybacks | Production homes, prescriptive code | High-performance, Net Zero, multi-shower |
*Have a 4-inch vertical stack (common in multi-level luxury homes or stacked residential units)? Specify the 4" diameter ThermoDrain TD442 (42" length, 46.20% efficiency, < 2.5 psi drop).
Ready to Integrate ThermoDrain on Your Next Project?
Whether you are an individual homeowner upgrading your hot water comfort or a builder ordering by the truckload, our technical team is ready to assist.