See it at Amerec: AK4.5
Amerec's own page for the AK4.5. Not a paid link.
AK4.5 vs MS90R
Amerec AK4.5 and Mr. Steam MS90R, compared on the figures their makers publish. Both are steam generators, and the room sizes their makers state, before each maker's own sizing rule, overlap.
The makers' figures side by side
| Specification | Amerec AK4.5 | Mr. Steam MS90R |
|---|---|---|
| Heater output | Watts: 4500 (240 V); 4500 (208 V) | kW: 5 |
| Room size the maker rates it for | Steam Room Cu Ft: Min 60, Max 90 | Room Volume (cu. ft.): 0 to 71 |
| Voltage | 240 and 208 volt models can be wired in the field for 1 or 3 phase power. | 2401 after model number denotes a 240V/1PH generator; B1 after model number denotes a 208V/1PH generator; Other voltage and phase combinations available upon request |
| Breaker / current | 240 V: 1 Phase Amps 19, Breaker 30; 3 Phase Amps 11, Breaker 15. 208 V: 1 Phase Amps 22, Breaker 30; 3 Phase Amps 12, Breaker 20 | Amps 240/1PH: 21; Wire Size AWG: 10 |
| Dimensions | 16-1/2" x 6-1/4" x 15" | 14.5" x 14.75" x 6.75" |
| Weight | — | Shipping Weight: 27 lbs. |
| Water and drain connections | Water Inlet – 3/8” NPT; Pressure Relief Valve – 3/4” NPT; Steam Outlet – 1/2” NPT; Drain Outlet – 3/4” NPT | Steam Outlet (3/4" NPT) Water Supply (3/8" NPT) Safety Valve (3/4" NPT) Steam Head (3/4" NPT) Drain (1/2" NPT) |
| Control included | 1 Control Required, additional may be connected. Compatible with the K2, K3, KT3, K4 controls. | Required Equipment: SteamX, iTempoTouch, TempoFlex, iTempo, Controls |
| Drain and flush | Amerec’s ADK auto drain option is highly recommended to automatically drain and flush the generator after every steam bath; If you do not buy the auto drain, your tank will need to be flushed monthly, or more often, depending on local water conditions | Optional Equipment: ChromaX, AudioX, Recessed Light, MS Wallseat, AutoFlush, Drip Pan |
| Safety listing | ETL Listed for USA and Canada | US and Canadian UL listed, and CE and NOM certified |
| Warranty | Limited Lifetime Warranty; all component parts for five years from the date of installation | Limited lifetime generator parts warranty |
| Price on the maker's site | $2,945 (steam builder on amerec.com, 29 Sep 2026) | $3,075 (List Price, Mr. Steam 2025 price book on docs.mrsteam.com, read 29 Sep 2026) |
Each figure is the maker's own, as cited row by row on the AK4.5 and MS90R pages and listed in the sources below. A dash means the figure is not on the maker pages we cite. Each maker states its own sizing rule, if any; read it on the product page.
Where to buy
See it at Mr. Steam: MS90R
Mr. Steam's own page for the MS90R. Not a paid link.
Where the published figures differ
- Heater output: AK4.5: Watts: 4500 (240 V); 4500 (208 V). MS90R: kW: 5.
- Room size the maker rates it for: AK4.5: Steam Room Cu Ft: Min 60, Max 90. MS90R: Room Volume (cu. ft.): 0 to 71.
- Voltage: AK4.5: 240 and 208 volt models can be wired in the field for 1 or 3 phase power. MS90R: 2401 after model number denotes a 240V/1PH generator; B1 after model number denotes a 208V/1PH generator; Other voltage and phase combinations available upon request.
- Breaker / current: AK4.5: 240 V: 1 Phase Amps 19, Breaker 30; 3 Phase Amps 11, Breaker 15. 208 V: 1 Phase Amps 22, Breaker 30; 3 Phase Amps 12, Breaker 20. MS90R: Amps 240/1PH: 21; Wire Size AWG: 10.
- Dimensions: AK4.5: 16-1/2" x 6-1/4" x 15". MS90R: 14.5" x 14.75" x 6.75".
- Water and drain connections: AK4.5: Water Inlet – 3/8” NPT; Pressure Relief Valve – 3/4” NPT; Steam Outlet – 1/2” NPT; Drain Outlet – 3/4” NPT. MS90R: Steam Outlet (3/4" NPT) Water Supply (3/8" NPT) Safety Valve (3/4" NPT) Steam Head (3/4" NPT) Drain (1/2" NPT).
- Control included: AK4.5: 1 Control Required, additional may be connected. Compatible with the K2, K3, KT3, K4 controls. MS90R: Required Equipment: SteamX, iTempoTouch, TempoFlex, iTempo, Controls.
- Drain and flush: AK4.5: Amerec’s ADK auto drain option is highly recommended to automatically drain and flush the generator after every steam bath; If you do not buy the auto drain, your tank will need to be flushed monthly, or more often, depending on local water conditions. MS90R: Optional Equipment: ChromaX, AudioX, Recessed Light, MS Wallseat, AutoFlush, Drip Pan.
- Safety listing: AK4.5: ETL Listed for USA and Canada. MS90R: US and Canadian UL listed, and CE and NOM certified.
- Warranty: AK4.5: Limited Lifetime Warranty; all component parts for five years from the date of installation. MS90R: Limited lifetime generator parts warranty.
- Price on the maker's site: AK4.5: $2,945 (steam builder on amerec.com, 29 Sep 2026). MS90R: $3,075 (List Price, Mr. Steam 2025 price book on docs.mrsteam.com, read 29 Sep 2026).
Figures we cite for only one of the two: weight (only Mr. Steam's cited pages give it). Ask the other maker before treating the two as equal on those points.
Read each one in full
Amerec AK4.5
Amerec · steam generator · 4.5 kW · rated by the maker for 60–90 cu ft
Mr. Steam MS90R
Mr. Steam · steam generator · 5 kW · rated by the maker for up to 71 cu ft
Sources
- Amerec: steam builder — Amerec
- Amerec: warranty — Amerec
- Amerec: Amerec AK Steam Generator with K2 and K3 (PDF) — Amerec
- Amerec: residential steam bath generator 100 — Amerec
- Amerec: faq — Amerec
- Mr. Steam: TS0041 90R 400R (PDF) — Mr. Steam
- Mr. Steam: PRICEBOOK (PDF) — Mr. Steam
- Mr. Steam: generators — Mr. Steam