The Energy Conservatory (TEC)

We manufacture MINNEAPOLIS brand precision diagnostic equipment and develop processes used to solve comfort, energy use, durability and air quality problems in buildings. Our knowledge of building physics, reputation for innovative design, and excellent technical support have made us the leading manufacturer of performance testing tools for the building science industry.



TEC products have a proven track record for innovation, reliability, accuracy and versatility

TEC continues to set the standard for specialized air flow and pressure measuring devices used to monitor and analyze the complex interactions which determine building performance. Innovative design and careful engineering have given TEC a reputation for designing the most reliable, accurate and respected line of performance testing products on the market today.

  • TEC pioneered the industry leading Minneapolis Blower Door™ and Duct Blaster® testing systems.
  • TEC is continually improving its highly acclaimed line of digital pressure gauges, most recently adding WiFi capability.
  • TEC has created a complementary line of air flow measurement tools including the TrueFlow® Air Handler Flow Meter, Exhaust Fan Flow Meter and FlowBlaster® Capture Hood Accessory.
  • TEC’s advanced set of testing and productivity apps and software tools give you the power meet all of your client’s testing and training needs.


Experience TEC

We provide the best and most accurate technical support

When you purchase TEC products, you are buying more than just the best designed building diagnostic tools. You are also buying our expertise, knowledge, superior service and commitment to quality.  Partner with TEC and experience the difference it makes working with the recognized industry leader.

TEC has an experienced staff of professionals with a wide range of technical skills and field experience. When you have questions on the use of our products or how to handle unusual situations you may encounter, you can count on us to give dependable answers. Our expertise goes beyond simply knowing our equipment. Our on-going research and close working relationship with the world’s leading building scientists has kept us actively involved in the development and field testing of many of the techniques currently being used in the performance testing industry. This experience ensures that our customers always have the most up to date information and testing procedures, and that we provide the very best technical support.

And if you ever have an equipment problem, we always stock a complete line of replacement parts, and can respond quickly to any service problem.


Who We Are


The TEC story

The idea for TEC was created in 1980 over lunches between partners Gary Anderson, then an auditor in St. Paul, and Gary Nelson, an engineer at the Minnesota Energy Agency, during which they would discuss the latest discoveries in residential energy efficiency. The blower door was one advance that captured their imagination.

Like so many great companies before it, TEC got its start in a garage where the two partners strove continuously to create a blower door design that would be more practical for mainstream contractors. That meant it had to be less expensive, lighter, and easier to use. They worked to make blower door testing more friendly, accurate, and efficient, and helped develop protocols for weatherization programs to prioritize air sealing efforts. Their efforts paid off and helped propel advances in construction and air sealing techniques that have become mainstream elements in both new construction and retrofit applications.

TEC quickly outgrew the garage business model and moved into a larger facility where innovation continued to flourish. During this time TEC developed many industry leading products including the first high precision two-channel digital pressure gauge and the first automated blower door testing system. In the late 1980s, TEC was in the forefront of research that led to the understanding that duct leakage is a big problem–not just for energy waste, but also because pressure imbalances caused by the duct system can result in back-drafting and indoor air quality problems. This realization led to the development of the Minneapolis Duct Blaster® system, the most widely used duct leakage testing system in the world.

In the summer of 2024 TEC moved into its current location in Oakdale, MN. Here the tradition of innovation continues with advances in performance testing equipment to quickly and accurately measure air handler flows, register and ventilation system flows and airtightness levels in large commercial buildings.


Overview of the diagnostic tools available from The Energy Conservatory

Product Milestones

July-17 The TEC Catalogs mobile app was released for both iOS and Android devices. This app allows for quick access to all TEC product brochures, manuals and quick guides.
July-17 TEC released a web-based Tubing Assistant tool to help reduce tubing hook-up mistakes.
Jan-17 Released the TEC Auto Test app for iOS devices. TEC Auto Test is designed for running an automated building envelope or duct leakage test and provides a report in PDF format. The Auto Test app will work with the DG-1000 as well as with a DG-700 that has a WiFi Link.
Sept-16 Released the TEC DG-1000 Pressure and Flow Gauge. The DG-1000 is a technological breakthrough running on a custom-built operating system, making it the most advanced tool for airtightness testing in the building performance industry.
Apr-14 Released the iTEC-700 Android mobile app for wireless air leakage testing using an Android mobile device.
Feb-14 Released Ring 4 for the Minneapolis Duct Blaster® for measuring air flow down to 2.4 cfm.
Jan-14 Released TECLOG3 Data Logging Software with wireless air leakage testing capabilities.
May-13 Released the iTEC-700 iOS mobile app for wireless air leakage testing using an iOS mobile device.
May-13 Released TECTITE 4.0 WiFi for wireless air leakage testing using a computer.
May-13 Introduced the TEC WiFi Link to wirelessly connect a DG-700 or DG-500 to a computer or mobile device.
Apr-13 Introduced iTEC RESNET Blower Door App for Android
Apr-12 Introduced iTEC RESNET Blower Door App for iPhone and iPad.
Jan-12 Introduced the FlowBlaster® Capture Hood attachment for the Duct Blaster which provided precision air flow measurements for residential HVAC registers.
Nov-11 Introduced the TEC Trainer Airtightness Testing Simulator making it easier to provide training for performance testing companies.
Aug-11 New Duct Blaster® Fan Speed Controller released. The new digital controller improves the ability to control fan speed and provide a Fan Control Port to allow Cruise Control of the Duict Blaster Fan.
Nov-10 Introduced TECLOG2 data logging software which includes multi-fan airtightness testing features for commercial Blower Door testing.
Nov-09 Added mini USB port to all DG-700 Pressure and Flow Gauges.
Jun-07 Introduced the Cruise feature on all DG-700 Pressure and Flow Gauges. Allows Minneapolis Blower Door fans to automatically adjust to and maintain a building pressure of 0, 25, 50 or 75 Pascals.
Mar-07 Added internal cooling fan to the digital Blower Door Fan Speed Controller.
Feb-04 Introduced the DG-700 Simulator software to control and display all of the features and buttons of the DG-700. Allowed trainers to show the DG-700 gauge on a projector through the computer.
Apr-03 Introduced the DG-700 digital pressure gauge which immediately became the most sophisticated and accurate pressure gauge on the market. Nine years later the DG-700 is still the premier pressure gauge to which every other product is compared.
Apr-01 Introduced the Exhaust Fan Flow Meter making it easy and inexpensive to accurately measure exhaust fan flows.
Mar-01 Introduced the TRUEFLOW® Air Handler Flow Meter which revolutionized total air handler flow measurements.
Jul-98 Introduced TECTITE PC based software which further raised the bar in computerized automated testing. TECTITE remains the gold standard for automated testing software.
Nov-97 Introduced the first computerized fully-automated Blower Door testing system (using AUTOAT software and APT system).
Feb-97 Introduced the Automated Performance Testing (APT) system and TECLOG software, the first accurate low-pressure measurement system specifically designed to data log changes in building pressures over time.
Mar-94 Introduced the DG-3 digital pressure gauge which added flow display features making testing easier and faster.
Jan-94 Introduced the first adjustable aluminum frame which made setting up for a Blower Door test easier than ever.
Nov-92 Introduced the DG-2 digital pressure gauge, the first digital 2 channel auto-zeroing gauge specifically designed for airtightness testing. Set the standard for pressure measuring devices.
Nov-92 Introduced the Minneapolis Duct Blaster® system which revolutionized airtightness testing of residential duct systems. The Duct Blaster remains the premier duct testing system 20 years later.
Jan-91 Introduced Model 3 Minneapolis Blower Door system with wood frame, Magnehelic gauges, Sharp calculator. Improved the accuracy of fan flow measurements.
Jan-84 Introduced Model 2 Minneapolis Blower Door™ system with wood frame, Magnehelic gauges, Sharp graphing calculator. The era of commercial Blower Door systems begins.

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