Della vs THERMAL ZONE heat pumps

Measured against models of the same size and duct type, THERMAL ZONE scores higher on 4 of the 6 ratings. Della has 22 outdoor models, THERMAL ZONE has 88 outdoor models. THERMAL ZONE has no QMID on file and is not ranked.

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CompareData as of Oct 11, 2026updated Oct 11, 2026 · sources

Against comparable models

Each cell is the share of same-size, same-type models that the manufacturer’s typical model beats (50% is typical); the higher score is in bold. Raw medians are underneath for context: they depend on which sizes each one makes, so they are not compared.

Della and THERMAL ZONE on every ratingPeer scores, 0–100 · grey ticks: every ranked manufacturer · shaded: the middle half of each one’s modelsMeasured against models of the same size and duct type, THERMAL ZONE scores higher on 4 of the 6 ratings.

Della
THERMAL ZONE
Other ranked manufacturers

Source: AHRI Directory, NEEP · as of Oct 11, 2026

Average peer percentile, raw median and rank among ranked manufacturers
Rating	Della	THERMAL ZONE
Efficiency index	39%median — · 27th ranked	43%median —
COP at 5°F	42%median 1.80 · 25th ranked	68%median 2.10
Capacity retention at 5°F	37%median 70% · 26th ranked	37%median 56%
HSPF2	23%median 8.5 · 27th ranked	31%median 7.5
SEER2	35% (higher)median 19.0 · 27th ranked	26% (higher)median 14.3
EER2	28%median 10.0 · 27th ranked	36%median 10.6
Heating capacity at 5°F	37%median 11,600 Btu/h · 26th ranked	40%median 19,900 Btu/h
Outdoor models	22	88
AHRI certifications	22	509

Share of models meeting each standard

Percent of each manufacturer’s models with a qualifying certification
Standard	Della	THERMAL ZONE
CEE 2025 Tier 1 (Split ASHP)	54.5%12 models	12.5%11 models
CEE 2026 Tier 1 (Split ASHP)	45.5%10 models	11.4%10 models
CEE Advanced Tier (Split ASHP)	0%0 models	0%0 models
Xcel Energy Colorado cold-climate ASHP (2025)	36.4%8 models	6.8%6 models
DOE Cold Climate Heat Pump Challenge	0%0 models	0%0 models
ENERGY STAR Cold Climate	18.2%4 models	21.6%19 models

Sizes and duct types offered

Models in each peer group, with the efficiency index of those models against the rest of the group.

Side by side, inside each size and duct typeShape: every model of the group · bars: each manufacturer’s middle half, median dot, 10th–90th line · 1 groups where both have models

Della
THERMAL ZONE
All models of the group

Raw ratings are only placed side by side within one size and duct type, where they are comparable.

Source: AHRI Directory · as of Oct 11, 2026

Models per peer group · efficiency index within the group
Size and duct type	Della	THERMAL ZONE
Ducted, up to 1.5 tons	None	8 · index 32%
Ducted, 2 tons	None	9 · index 42%
Ducted, 2.5–3 tons	None	27 · index 44%
Ducted, 3.5–4.5 tons	None	31 · index 46%
Ducted, 5 tons and up	None	12 · index 55%
Non-ducted, up to 1.5 tons	16 · index 43%	None
Non-ducted, 2 tons	3 · index 39%	None
Non-ducted, 2.5–3 tons	3 · index 27%	1 · index —

Cold-climate and all-around picks, size class by size class

Each manufacturer’s best model on each board in every size and duct type, side by side; the higher score is in bold. Both scores are 0–100 against every model of that size class (the line on each bar is 50, the typical model there), so the two compare fairly even when they make different sizes.

Cold-climate picks

Best cold-climate pick per size and duct type (keeps at least 70% of its heat at 5°F). Qualifies when its capacity retention at 5°F (capacity at 5°F as a share of capacity at 47°F) is at least 70% and Capacity retention at 5°F, COP at 5°F, HSPF2 are all rated. Score = the equal-weight mean of its peer percentiles on Capacity retention at 5°F, COP at 5°F, HSPF2 (share of the other models in its peer group it beats, 0–100), all from one certified pairing: in each duct type a model is sold in, its qualifying pairing of that type with the best score; equal scores (one decimal) go to the higher heating capacity at 5°F.
Size and duct type	DellaCold-climate score, best model	THERMAL ZONECold-climate score, best model
Ducted, up to 1.5 tons	No models in this size class	67.7(50 is the typical model of its size class)TZPLV182PAwith ducted air handler H,RG21924+TD1 of 8 models qualify · AHRI 214311494
Ducted, 2 tons	No models in this size class	66.5(50 is the typical model of its size class)TZPLV242PAwith ducted air handler TZHVLE2417JA2 of 9 models qualify · AHRI 211126503
Ducted, 2.5–3 tons	No models in this size class	78.6(50 is the typical model of its size class)TZPLV362PAwith ducted air handler MAC-36HWDN1-MN02 of 27 models qualify · AHRI 213885869
Ducted, 3.5–4.5 tons	No models in this size class	73.8(50 is the typical model of its size class)TZPLV482PAwith ducted air handler TZHVLE4821JA2 of 31 models qualify · AHRI 211126512
Ducted, 5 tons and up	No models in this size class	None on this board (0 of 12 models qualify)
Non-ducted, up to 1.5 tons	68.8(50 is the typical model of its size class)048-TP-12K2V-23S-OUTwith ductless indoor unit 048-TP-12K2V-23S-IN8 of 16 models qualify · AHRI 213927343	No models in this size class
Non-ducted, 2 tons	None on this board (0 of 3 models qualify)	No models in this size class
Non-ducted, 2.5–3 tons	None on this board (0 of 3 models qualify)	None on this board (0 of 1 models qualify)

All-around best

Best all-around model per size and duct type. Score = 50% heating, the mean of its peer percentiles on COP at 5°F, Capacity retention at 5°F, HSPF2, plus 50% cooling, the mean of its peer percentiles on SEER2 and EER2 (share of the other models in its peer group it beats, 0–100). All five ratings are required; there is no minimum heat kept at 5°F. In each duct type a model is sold in, it is scored on its pairing of that type with the best score; equal scores (one decimal) go to the higher cold-climate score, then the higher heating capacity at 5°F.
Size and duct type	DellaAll-around score, best model	THERMAL ZONEAll-around score, best model
Ducted, up to 1.5 tons	No models in this size class	63.4(50 is the typical model of its size class)TZPLV182PAwith ducted air handler TZHVLE1817JA6 of 8 models have all five ratings · AHRI 211126509
Ducted, 2 tons	No models in this size class	65.8(50 is the typical model of its size class)TZPLV242PAwith ducted air handler TZHVLE2417JA6 of 9 models have all five ratings · AHRI 211126503
Ducted, 2.5–3 tons	No models in this size class	58.0(50 is the typical model of its size class)TZPLAD1530AJNwith ducted air handler TZHDLVST3617*NAN10 of 27 models have all five ratings · AHRI 212508013
Ducted, 3.5–4.5 tons	No models in this size class	62.1(50 is the typical model of its size class)TZPLAD1548AJNwith ducted air handler TZHDLVST4821*NAN10 of 30 models have all five ratings · AHRI 212508016
Ducted, 5 tons and up	No models in this size class	67.6(50 is the typical model of its size class)TZP15AZ60AJ2Nwith ducted air handler TZHDLTST6024*NANAlso listed as TZPLAD1560AJN3 of 13 models have all five ratings · AHRI 211641701
Non-ducted, up to 1.5 tons	70.8(50 is the typical model of its size class)048-TP-12K2V-23S-OUTwith ductless indoor unit 048-TP-12K2V-23S-IN10 of 16 models have all five ratings · AHRI 213927343	No models in this size class
Non-ducted, 2 tons	53.0(50 is the typical model of its size class)048-TP-24K2V-20S-OUTwith ductless indoor unit 048-TP-24K2V-20S-IN2 of 3 models have all five ratings · AHRI 213927345	No models in this size class
Non-ducted, 2.5–3 tons	29.5(50 is the typical model of its size class)048-TL-36K-MODU3 of 3 models have all five ratings · AHRI 211042067	None on this board (0 of 1 models have all five ratings)

All-around board, every manufacturer

Standout model on each rating

Each manufacturer’s model that beats the largest share of comparable models on the rating; the higher share is in bold.

Top model per rating by peer percentile, with its AHRI-certified value and peer group
Rating	Della	THERMAL ZONE
COP at 5°F	beats 89% · 2.21048-TP-18K2V-22S-OUTNon-ducted, up to 1.5 tons	beats 90% · 2.50TZPLAD1560AJNDucted, 3.5–4.5 tons
Capacity retention at 5°F	beats 64% · 77%048-TP-9K2V-23S-OUTNon-ducted, up to 1.5 tons	beats 97% · 102%TZPLV362PADucted, 2.5–3 tons
HSPF2	beats 57% · 9.5048-TP-12K2V-23S-OUTNon-ducted, up to 1.5 tons	beats 93% · 10.0TZPLV362PADucted, 2.5–3 tons
SEER2	beats 79% · 23.5048-TP-9K2V-23S-OUTNon-ducted, up to 1.5 tons	beats 70% · 16.0TZP15AZ60AJ2NAlso listed as TZPLAD1560AJNDucted, 5 tons and up
EER2	beats 68% · 13.0048-TP-9K2V-23S-OUTNon-ducted, up to 1.5 tons	beats 78% · 11.7TZP15AZ60AJ2NAlso listed as TZPLAD1560AJNDucted, 5 tons and up
Heating capacity at 5°F	beats 78% · 13,000 Btu/h048-TL-18K-MODUNon-ducted, up to 1.5 tons	beats 95% · 48,500 Btu/hTZPLV602PADucted, 3.5–4.5 tons

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