TETCO ES4-X Series Indoor Split unit image 5 year warranty

ES4-X Series Indoor Split

The ES4-X Series Indoor Split system offers unparalleled flexibility of installation for new construction and replacement applications. The unit can be used in conjunction with a conventional furnace/air conditioner to create a hybrid heating system.


  • Solid brass service valves
  • Copeland® UltraTech® two-stage scroll compressor
  • High-style white powder coated steel cabinet
  • Removeable panels for easy access
  • Flow switch protected
  • Digital controls
  • Standard hot water generator (desuperheater)
  • 1" FPT fittings


Model Capacity Cooling Heating
Btu/hr EER Btu/hr COP
TST024 Full Load 24,900 15.4 17,800 3.4
Part Load 18,300 22.1 14,100 3.7
TST036 Full Load 38,000 16.5 28,400 3.7
Part Load 28,900 23.9 22,600 4.2
TST048 Full Load 48,600 18.7 35,900 3.8
Part Load 39,400 26.4 27,900 4.2
TST060 Full Load 62,200 16.8 44,200 3.5
Part Load 47,400 22.5 34,700 3.9
TST072 Full Load 68,000 15.7 51,800 3.4
Part Load 53,600 21.8 41,900 3.7
Unit Notes
  • Rated in accordance with ISO Standard 13256-1, which includes pump penalties.
  • Heating capacities based on 68.0°F DB, 59.0°F WB entering air temperature.
  • Cooling capacities based on 80.6°F DB, 66.2°F WB entering air temperature.
  • Entering water temperatures Full Load: 32°F heating / 77°F cooling.
  • Entering water temperatures Part Load: 41°F heating / 68°F cooling.


Programmable thermostat

Keeps the home more comfortable by operating the unit on a set schedule and temperature range. This also saves on energy costs by setting the unit back while the home is unoccupied.

Non-programmable thermostat

Designed to take maximum advantage of the multi-stage functionality of the unit. This allows the unit to achieve maximum savings by only operating at the right range to match the current weather.

Auxiliary internal electric heater

Adds that little bit of extra heat on those few coldest days. Also helps to balance the system size by balancing out those few extreme days. With a standard stab-in design, you don't have to drop the blower to install.

Auxiliary external electric heater

Adds that little bit of extra heat on those few coldest days. Also helps to balance the system size by balancing out those few extreme days. These heaters are installed in the supply air duct outside of the unit. Mostly used on horizontal style equipment.

Flow centers - pressurized

Circulates the fluid through the unit and the geothermal loop field. These types form a completely closed system.

Flow centers - non-pressurized

Circulates the fluid through the unit and the geothermal loop field. This type of system uses an expansion tank that can be topped off should the loop require it due to thermal expansion.

EWC zone control

These highly sophisticated controls work with dampers in the ductwork to create multiple zones throughout the house. You can utilize one unit, but have different temperatures in each zone. The control panel controls both the unit, and the zone dampers.

Unit air pad (plastic or foam)

The unit air pad creates a buffer between the unit and the home. This buffer prevents any vibration from the unit to be transmitted into the home which improves the already quiet operation of the unit.

Electrostatic filter (washable)

This type of filter is a permanent media filter that can be washed from time to time as needed. This eliminates the need to buy new filters.

Electronic 24 volt air cleaner

This type of filter uses an electrically charged media to increase filtration performance. This improves indoor air quality by removing more particles from the airstream. This filter requires the occasional media replacement.

Disposable pleated filter

This type of filter uses a pleated media to remove dust and other particles from the air stream. It is important to check these filters regularly and replace them as needed.

Air handler (DX refrigerant or hydronic)

These multi-positional air handlers are specially matched to our split systems for maximum performance. The match also qualifies the system for the 30% U.S. federal tax credit. The air handler can be installed in remote parts of the home, or hard to reach areas where space is at a premium.

"A" coil (DX refrigerant or hydronic)

The specially matched "A" coil allows the split geothermal system to be added to an existing air handler or furnace in retrofit applications. Additionally, the "A" coil can allow the system to operate in a dual-fuel application where backup heat is supplied by a traditional furnace.

Extended warranty

Adds that extra peace of mind by extending the standard warranty to a full 10 years on parts and labor.

Consumer purchase plans

With a wide variety of payment options and terms, our consumer payment plans make installing a geothermal system easier and more cost effective. By deferring your initial payments out, you can start enjoying your new system earlier and take time to obtain many of the various rebates and tax credits offered.