SplitAtlas

Pioneer / Diamante Pro

Pioneer Diamante Pro 9k R-454B 115V Mini-Split

Certified capacity
9,000 BTU/h[4]
SEER2
19 SEER2[4]
Heating floor
-4 F[2]
Voltage
115 V[1]
Install path
Professional install

The Diamante Pro 9k on 115V is the plug-into-a-normal-circuit option in Pioneer's mid tier, which is the main reason to choose it - no new 230V run means a materially cheaper install. SEER2 19 and a -4F heating floor put it above the Essenza line and below Quantum.

For a small bedroom or office in a moderate climate that is a sensible middle. If the room ever needs to hold heat below freezing, the Quantum Ultra 9k 115V keeps the same circuit and adds nine degrees.

1 zoneProfessional installCurrent

Refrigerant generation

R-454B - current-generation refrigerant

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$858 / Fresh price - checked Jul 24, 2026

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Pioneer Diamante Pro 9,000 BTU R-454B 115V (WT009ALSI20HLF / YN009ALSI20RPF) mini-split heat pump indoor wall unit and outdoor condenser

Image: Pioneer

Data completeness: 100%
Last sourced
Jul 24, 2026

SplitAtlas score

7.5 / 10

Methodology
Cooling efficiencyBottom quartile

(19.0 SEER2) among <=9k systems

Heating efficiencyBelow average

(9.5 HSPF2) among <=9k systems

Cold-weather performanceBottom quartile

(73% heat retained at 5F; -4 F heating floor) among <=9k systems

NoiseBottom quartile

(28 dBA indoor min / 54 dBA outdoor) among <=9k systems

Feature setTop quartile

(6 verified features) across the catalogue

Price-to-performanceBelow average

($858 median retail) among <=9k systems

Documentation & partsBelow average

(6 manuals; spec sheet) across the catalogue

Not evaluated

  • Installation accessibility — not applicable (professional install)N/A

    professional install - DIY-accessibility not applicable

Key ratings

Rated cooling

9,000BTU/h[4]

Rated heating

10,000BTU/h[4]

Buyer review snapshot

Install difficulty

Professional install
  • Electrical: 115V; breaker/fuse 25 A.
  • Line set: connection type not sourced; included 16 ft; max 50 ft.

Alternatives

Availability and price context

  • Verified current price: $858.00 at Pioneer; availability in_stock; checked Jul 24, 2026.

Source date

Model data sourced
Jul 24, 2026
Page reviewed
Jul 23, 2026
Source-backed records
5
Newest source retrieved
Jul 24, 2026

Warranty tiers

Warranty: Up to 5-year Pioneer warranty for registered eligible Diamante Pro systems.

Review methodology

Model context

Structured ratings
Certification: ENERGY STAR certified and AHRI cold-climate designated. Refrigerant: current low-GWP R-454B. Minimum heating ambient: -4 F.

Strengths

  • 115V, so no new circuit and a cheaper install.
  • Current R-454B refrigerant.
  • -4F rated heating, well ahead of the Essenza line.

Weaknesses

  • SEER2 19 is the lowest in the Diamante Pro line.
  • Quantum Ultra 9k is also 115V and holds -13F for a modest step up.

Climate suitability

Minimum heating ambient
-4 F[2]
Rated heating at 5F
7,300 BTU/h[4]
Rated heating at 17F
8,000 BTU/h[4]
Rated heating at 47F
10,000 BTU/h[4]

Specifications

Show
Manufacturer
Pioneer
Brand
Pioneer
Product line
Diamante Pro
Model number
WT009ALSI20HLF indoor / YN009ALSI20RPF outdoor
Indoor unit model
WT009ALSI20HLF
Outdoor unit model
YN009ALSI20RPF
Number of zones
1
Max indoor units
not published
Rated cooling capacity
9,000 BTU/h[4]
Rated heating capacity
10,000 BTU/h[4]
Voltage
115 V[1]
MCA
not published - manufacturer specifies 25 A breaker
Maximum fuse or breaker size
25 A[1]
Breaker needed
25 A[1]
SEER2
19 SEER2[4]
EER2
11.7 EER2[4]
HSPF2 (Region 4)
9.5 HSPF2[4]
HSPF2 (Region 5)
not published
COP
not published
COP at 47F
not published
COP at 5F
1.9 COP[4]
Minimum outdoor heating temperature
-4 F[2]
Minimum outdoor cooling temperature
5 F[2]
Maximum outdoor temperature
122 F[2]
Indoor noise range
42/40/35/30/28 dB(A)[2]
Outdoor noise rating
54 dBA[1]
Indoor weight
19.8 lb[1]
Outdoor weight
51.8 lb[1]
Refrigerant
R-454B[4]
Refrigerant charge
not published
Manufacturer coverage
not published
Line-set size
1/4 in liquid / 3/8 in suction
Included line-set length
16 ft[1]
Maximum line-set length
50 ft[2]
Max line set per indoor
not published
Maximum elevation difference
33 ft[2]
Max height between indoor units
not published
Wi-Fi support
supported[3]
Energy Star status
ENERGY STAR certified[5]
AHRI certification number
217048740[4]
Warranty
Up to 5-year Pioneer warranty for registered eligible Diamante Pro systems.
Install path
Professional install
Retail price
$858.00
Available retailers
Pioneer
Manual links
WYT009ALSI20RL AHRI certificate, WYT009ALSI20RL EnergyGuide, WYT20 installation manual, WYT20 service manual, WYT009ALSI20RL submittal sheet, WYT20 technical brochure
Specification sheet
WYT009ALSI20RL submittal sheet
Last sourced date
Jul 24, 2026

Retail purchase context

Some retailer links may earn us a commission at no extra cost; paid relationships never change scores or recommendations. Affiliate disclosure

Paid link

Check price at Pioneer

$858 / Fresh price - checked Jul 24, 2026

Electrical requirements

Show
Voltage
115 V[1]
Voltage range
115V[1]
Phase
1[1]
Frequency
60 Hz[1]
MCA
not published - manufacturer specifies 25 A breaker
Breaker needed
25 A[1]
Maximum breaker size
25 A[1]
Maximum fuse size
25 A[1]
Maximum cooling current
6.8 A[2]
Maximum heating current
6.8 A[2]
Manufacturer wire notes
not published

Installation considerations

Show
Liquid line
1/4 in[1]
Suction line
3/8 in[1]
Line connection type
not published
Precharged length
not published
Included line-set length
16 ft[1]
Maximum line-set length
50 ft[2]
Max line set per indoor
not published
Max height between indoor units
not published
Indoor dimensions
31-7/8 x 8 x 11-1/2 in[1]
Outdoor dimensions
31 x 11-1/2 x 19-3/8 in[1]
Indoor weight
19.8 lb[1]
Outdoor weight
51.8 lb[1]
Drain size
not published

Frequently asked questions

Can I install the Pioneer Diamante Pro 9,000 BTU R-454B 115V (WT009ALSI20HLF / YN009ALSI20RPF) myself, or do I need a pro?
Pioneer Diamante Pro 9,000 BTU R-454B 115V (WT009ALSI20HLF / YN009ALSI20RPF) is built for professional installation: the line set must be flared, evacuated, and charged, which requires EPA-certified refrigerant handling. Installing it outside the manufacturer's requirements can void the warranty, so budget for a qualified HVAC installer.
Will the Pioneer Diamante Pro 9,000 BTU R-454B 115V (WT009ALSI20HLF / YN009ALSI20RPF) keep heating in a cold winter?
The manufacturer publishes 7,300 BTU/h of heating output at 5F. Rated heating operation extends down to -4 F. Certified heating efficiency is 9.5 HSPF2. Match those numbers against your climate's design temperature - in cold regions, output at 5F matters far more than the nameplate capacity measured at 47F.
What electrical circuit does the Pioneer Diamante Pro 9,000 BTU R-454B 115V (WT009ALSI20HLF / YN009ALSI20RPF) need?
Published electrical requirements: 115 V voltage, not published - manufacturer specifies 25 A breaker minimum circuit ampacity, and 25 A maximum breaker or fuse sizing. Confirm the final circuit against the unit nameplate and local code with a licensed electrician.
How far can the outdoor unit be from the indoor head?
The published maximum line-set length is 50 ft, and the included line set comes pre-charged for 16 ft. Longer runs than the included set allows typically mean added refrigerant and a pro visit, so measure the planned routing before ordering.

Data sources

Show
  1. Pioneer Mini Split: Diamante Pro WYT009ALSI20RL product pageSourced - manufacturer product page

    Covers Breaker needed, Frequency, Maximum breaker size, Maximum fuse size, Phase, Voltage and more

  2. Pioneer / Parker Davis HVAC International, Inc.: WYT009ALSI20RL submittal sheetSourced - manufacturer technical document

    Covers Maximum cooling current, Maximum heating current, Indoor noise range, Maximum elevation difference, Maximum line-set length, Minimum outdoor cooling temperature and more

  3. Pioneer Mini Split: Pioneer wall-mounted mini-split model comparison guideSourced - manufacturer product page

    Covers Wi-Fi support, Legacy compressor warranty value, Legacy warranty value, Warranty notes

  4. Air-Conditioning, Heating, and Refrigeration Institute: AHRI Appendix M1 public row for YN009ALSI20RPF / WT009ALSI20HLFSourced - AHRI directory

    Covers AHRI certification number, performance_spec.cold_climate_designation, Rated cooling capacity, COP at 5F, EER2, Rated heating capacity and more

  5. ENERGY STAR: ENERGY STAR exact row check for AHRI 217048740Sourced - Energy Star listing

    Covers Energy Star status

Last updated

Jul 23, 2026