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Thermal-storage systems

Add thermal storage and get up to $75 per kilowatt in rebates.

Store energy and get rebates

Thermal-storage systems allow for heating (or cooling) to be created during off-peak hours and then used as needed—saving you money with off-peak rates and thermal-storage rebates!

How it works

Install a thermal-storage system in your home or business and become eligible for both off-peak rates and associated rebates. Thermal-storage system options include:

  • Underfloor heat storage.
  • Hydronic heat storage.
  • Central thermal-storage furnaces.
  • Thermal-storage room units.

Thermal-storage cooling systems—most often used in commercial cooling systems—are also eligible.

Eligibility and details

To be eligible for a rebate, a thermal-storage system must take advantage of a qualified off-peak rate.

  • Get a $75-per-kilowatt (kW) rebate for storage technologies served on our Deferred Load, Residential Demand Control (RDC), or Fixed Time of Delivery Rates.
  • Get a $40-per-kW rebate for storage technologies served on our Dual Fuel Rates.

Your system must have adequate storage capacity to fully heat or cool during the maximum control period allowed by the rate serving the system. Electric cable or panel storage rebates are limited to under slab installations with storage capacity (usually in several inches of sand beneath the slab).

Rebate requirements

  • Minimum installation size of 9 kW.
  • Maximum rebate is 500 kW in North Dakota and South Dakota.
  • Rebates totaling more than $10,000 require prior approval.
  • In a combined thermal-storage/air-source heat pump system, rebate applies only to the thermal-storage load. Heat pump systems are rebated separately.

Apply for your rebate

Contact our Idea Center or call 800-493-3299 for questions during business hours.

Once your installation is complete, fill out the rebate form and attach all required documentation, then mail it to: 

Otter Tail Power Company
P.O. Box 496
Fergus Falls, MN 56538

2024 thermal-storage rebate form

Please allow 6-8 weeks for your rebate check to arrive.

Related programs

Residential Business

Deferred Load Rate

Store now, use later—save up to 30% on your heating and cooling costs by switching to our Deferred Load Rate.

Electric heating rebates

Rebates are available for several electric-heating technologies.

Fixed Time of Delivery Rate

Set your energy delivery to off-peak hours to store heating and cooling power for the day—all at one of our lowest prices.

Heat pump rebates

Install the most efficient and environmentally friendly heating and cooling system on the market and start saving big!

Related topics

Central thermal-storage furnace

Specially-designed ceramic bricks help efficiently and economically store heat for any sized home or business.

In-floor hydronic heat

Using the power of water to create and store heat within your building’s heating system.

Thermal-storage cooling

Store cooling for future use, and benefit from significant savings.

Thermal-storage room units

Room-by-room control and the comfort from a thermal-storage system.

Underfloor heat storage

Warm feet, dust-free, and totally efficient, underfloor heat storage creates a heat reservoir under your building.