CPC technology class · F24

F24D - Domestic- Or Space-heating Systems

Domestic- or space-heating systems, e.g. central heating systems; domestic hot-water supply systems; elements or components therefor. 2,041 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

2,041
US patents granted: #5/8
in F24: 7.5%
F24 class share: +6%
5-yr velocity

The verdict

According to USPTO PatentsView, Domestic- Or Space-heating Systems ranks #367 of 670 CPC technology areas - 2,041 US patents granted since 2015, with recorded grant volume up 6% over five years.

#367
of 670 CPC technology areas: 2,041
US patents granted, 2015–2025: Mitsubishi Electric
leading assignee (84): +6%
grant velocity, last 5 yrs

How F24D's grant cadence moved

Between 2020–2024, F24D recorded 967 grants versus 913 in 2015–2019 (+6% equal-window velocity). Across complete years, output peaked in 2024 at 213 grants and bottomed in 2015 at 135 (+58% peak-over-trough). Lead assignee Rheem Manufacturing Company holds 4.0% of the class ; the top three share 8.1%.

Leaderboard read

F24D concentration, lead at 4.0%

Rheem Manufacturing Company leads this historical grant record at 4.0% of F24D - foreign corporation assignees hold 51% of class grants (492 of 957). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 4.0%
Top three share: 8.1%
Lead over #2: 36

Where F24D sits inside F24

Among 8 subclasses in F24 (HEATING; RANGES; Ventilating), F24D ranks #5 and holds 7.5% of the parent class's 27,261 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F24F 14,049 F24C 3,868 F24S 3,307 F24H 2,950 F24T 436 F24B 409 F24V 201

Rising assignees active in F24D

Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.

#1 Hamfop Technologies LLC 6.00x 0 → 6 company-wide · 6 in F24D
#2 Rinnai America Corporation 5.67x 3 → 17 company-wide · 12 in F24D
#3 Octopus Energy Heating Limited 5.00x 0 → 5 company-wide · 13 in F24D
#4 AquaMotion, Inc. 4.00x 2 → 8 company-wide · 6 in F24D
#5 Giacomini S.p.A 4.00x 2 → 8 company-wide · 5 in F24D

F24D grants by year, peak 2024 (213)

US utility-patent grants per year in F24D, 2015–2025 - recent five years are up 6% versus 2015–2019.

Rheem Manufacturing

81
Noritz

45
Grundfos Holding A/S

40
Lennox Industries

36
Adey Holdings (2008)

31
Trane International

28
Kyungdong Navien

27
Intellihot

26
E On Sverige Ab

24
A O Smith

18
Progress Profiles Spa

18
Watts Regulator

16

What this shows Mitsubishi Electric is the most active filer in F24D, holding 84 of the 2,041 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass F24D
Rank	Company	Patents in F24D
#1	Rheem Manufacturing Company	81
#2	Noritz Corporation	45
#3	Grundfos Holding A/S	40
#4	Lennox Industries Inc.	36
#5	Adey Holdings (2008) Limited	31
#6	Trane International Inc.	28
#7	Kyungdong Navien Co., Ltd.	27
#8	Intellihot, Inc.	26
#9	E.ON Sverige AB	24
#10	A. O. Smith Corporation	18
#11	Progress Profiles SPA	18
#12	Watts Regulator Co.	16
#13	Ademco Inc.	15
#14	Rinnai Corporation	15
#15	Belimo Holding AG	15
#16	Rheem Australia PTY Limited	13
#17	Octopus Energy Heating Limited	13
#18	Nibco Inc.	12
#19	Rinnai America Corporation	12
#20	Emerson Electric Co.	11

Footprint here vs. claim strategy

Each dot is a leading F24D assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 F24D assignees by class footprint. Bubble size = patents in F24D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F24D's 2,041-grant footprint

Nationwide nearest neighbors for F24D (#367 of 670 by volume ; lead share 4.1%) - not the F24 parent-class siblings above.

Nearest by grant volume

B31B 2,038 H05G 2,073 A23G 1,990 H01C 2,105

Nearest by lead-assignee share

B06B 4.1% G08C 4.1% E04F 4.1% B29L 4.1%

Questions about F24D

Which company holds the most patents in F24D?

Mitsubishi Electric Corporation leads F24D with 84 patents (4.0% of the subclass). By PatentsView assignee type, foreign corporations account for 51% of class grants.

Which F24D assignees grew fastest recently?

Among assignees with ≥5 grants in F24D, Hamfop Technologies LLC shows the highest company-wide grant multiple (6.00x: 0 grants in 2019–2021 → 6 in 2022–2024) while holding 6 patents in this subclass. Growth is company-wide, not class-only.

How does F24D compare inside parent class F24?

Inside F24 (HEATING; RANGES; Ventilating), F24D ranks #5 of 8 subclasses by grant volume and holds 7.5% of the parent class total. The largest sibling is F24F (14,049 grants).

What to do with this data

F24D in context - here's where to go next.

Rheem Manufacturing Company leads F24D with 81 grants in this class. See full portfolio
F24D ranks #367 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class F24, the largest sibling subclass is F24F with 14,049 grants. Explore F24F

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - F24D figures are USPTO PatentsView granted-utility totals for this subclass (2,041 grants in the tracked window).

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.