grid deduction - Double feature: Hot stuff

_{This puzzle is part 4 of the Double feature series (first part here). The series will continue in "Double feature: In cold blood".}

---

Rules of Heyawake¹

• Shade some cells in the grid.


• Inside each room (rectangle with bolded borders), the number indicates how many shaded cells there are inside that room. If there is no number, the number of shaded cells is unknown.


• Shaded cells cannot be connected horizontally or vertically, but they may touch at a corner.


• Unshaded cells must all be orthogonally connected.


• It is not possible draw a straight horizontal or vertical line on unshaded cells so that the line goes inside more than two rooms.

Across
2. Experiment to abruptly reconstruct curved structure (8)
6. Move silently as serpent's tail creeps forward (5)
7. Maxim watched a horror film (3)

8. They're useful documents – the reverse of junk (4)
9. Noblemen not having all internal organs (4)
11. Reboots to uses of silence in music with creative expression (8)
13. Cook a little fish (3)
14. The man standing before a cross reveals a witch (3)

Down
1. Cards for axe-wielding novelist and his portrayer (5)
2. Mountain with extra charge on top (8)
3. Pronounced footprints leading to grasslands (7)
4. "Special Tacos with Coffee" – a chain of cafés (5)

5. Utter exploit of females (4)
9. Shade is essential to recruitment (4)
10. Record a part of Montenegro's territory (6)
12. Broken hand at first leaves annoyance in the flesh (4)

_{¹ Paraphrased from the original rules on Nikoli.}

Solve both puzzles to answer the question: What is 80 degrees Celsius?

Answer

so apparently 80 degrees Celsius is

a SAUNA'S TEMPERATURE.

Oops! I forgot to put in explanations for the cryptic clue solutions. Here they are:

2a. RESE(-t)+ARCH. 6a. SNAKE with E moved earlier. 7a. triple def. 8a. SPAM<. 9a. EARLS minus (-a)L(-l). 11a. REST+ARTS. 13a. double def. 14a. HE+X.
1d. Jack {Torrance, Nicholson}. 2d. RUSH+MORE. 3d. homophone of STEPS. 4d. TACOS*, "Costa Coffee". 5d. homophone of USE. 9d. substring. 10d. substring. 12d. THORN minus H(-and).

(Thanks to Avi for pointing out in comments that I missed a letter.)